Outside groups have accounted for almost half of all ad spending during this presidential general election, according to a First Read analysis of data provided by ad-buying firm SMG Delta.

Groups supporting the presidential candidates but not affiliated with the campaign, including super PACs, have spent $267 million of the $605.7 million spent on television and radio ads.

(That overall number is sure to climb, as the Romney campaign is booking buys today.)

That means about 44 cents of every dollar spent on ads this election has come from outside groups.

There’s a big difference between who they’re supporting. Three-quarters of all money spent by outside groups -- $212 million -- has gone to support Republican presidential nominee Mitt Romney.

Two-thirds of all the ads run to support Romney, including the campaign, have come from outside groups. By contrast, 20 percent of ads supporting President Barack Obama’s re-election effort have come from outside groups.

OVERALL SPENDING: $605.7 million

Team Obama $286,905,268
Team Romney $318,396,978

OUTSIDE SPENDING: $266,782,619 (44 percent of total)

Team Romney $212,458,408 (67 percent of total)
Team Obama $57,473,660 (20 percent of total)

Outside groups’ spending tracks with the campaigns in some ways with heavy spending in Florida, Ohio, and Virginia. But in states where the campaigns aren’t spending heavily, outside groups have stepped in to account for most of the political advertising to test out messages and try to move the needle, so to speak.

Florida, like with the campaigns, is seeing the most total spending from outside groups -- $58.6 million. That’s just about half of the $121 million total spent in the state.

Next up in total spending: Ohio $42.6 million, Virginia $33.3 million, Colorado $25.1 million, North Carolina $21.2 million, Iowa $19 million, Pennsylvania $14.4 million, Nevada $14.2 million, Wisconsin $13.4 million, New Hampshire $11.9 million, Michigan $10 million.

By percentage of total spending in that state: Michigan 99.9 percent, Wisconsin 92 percent, Pennsylvania 75 percent, Colorado 44 percent, Wisconsin 42 percent, Iowa 40 percent, Virginia 37 percent, North Carolina 37 percent, Nevada 37 percent, Ohio 36 percent.

Strikingly, in every state, outside groups have made up a majority of all ads supporting Romney. In Florida, in particular 73 percent of all ads supporting Romney have come from outside groups.

Though the Obama campaign has spent a whopping $46 million in Florida, outside groups have helped Romney even the score. The Crossroads groups have poured in more than $25 million, the Koch-brothers-backed Americans for Prosperity $9 million, Restore Our Future $8 million, America’s Future Fund $1.4 million, and the American Energy Alliance $850,000. They have combined with the Romney campaign for $60.3 million in the Sunshine State, about what Obama has spent with the help of outside groups -- $60.7 million.

The Obama campaign has gotten some help from outside groups in Florida, but not to the level Romney is benefitting. Priorities USA has spent $12.7 million there, followed by the SEIU $1.5 million, Planned Parenthood $450,000, and MoveOn.org $64,000.

Here’s how it breaks down by state (plus a grand total of how much each group has spent below that): 

FLORIDA
OVERALL SPENDING: $121 MILLION
OUTSIDE GROUP SPENDING: $58.6 MILLION (48 percent of total) 

OUTSIDE GROUP BREAKDOWN:
PRO-ROMNEY: $43.8 MILLION OF $60 MILLION (73 percent)
PRO-OBAMA: $14.7 MILLION OF $60.7 MILLION (24 percent) 

OHIO
OVERALL SPENDING: $116.9 MILLION
OUTSIDE GROUPS SPENDING: $42.6 MILLION (36 percent)

OUTSIDE GROUP BREAKDOWN:
PRO-ROMNEY: $29.9 MILLION OF $53.3 MILLION (56 percent)
PRO-OBAMA: $12.7 MILLION OF $63.6 MILLION (20 percent) 

VIRGINIA
OVERALL SPENDING: $90.3 MILLION
OUTSIDE GROUP SPENDING: $33.3 MILLION (37 percent) 

OUTSIDE GROUP BREAKDOWN:
PRO-ROMNEY: $22.4 MILLION OF $42.4 MILLION (53 percent)
PRO-OBAMA: $10.9 MILLION OF $47.9 MILLION (23 percent) 

COLORADO
OVERALL SPENDING: $57 MILLION
OUTSIDE GROUP SPENDING: $25.1 MILLION (44 percent) 

OUTSIDE GROUP BREAKDOWN:
PRO-ROMNEY: $16.4 MILLION OF $27.5 MILLION (60 percent)
PRO-OBAMA: $8.6 MILLION OF $29.5 MILLION (29 percent)

NORTH CAROLINA
OVERALL SPENDING: $57.7 MILLION
OUTSIDE GROUP SPENDING: $21.2 MILLION (37 percent) 

OUTSIDE GROUP BREAKDOWN:
PRO-ROMNEY: $21.2 MILLION OF $35.5 MILLION (60 percent)
PRO-OBAMA: $10.9 MILLION OF $47.9 MILLION (23 percent) 

IOWA
OVERALL SPENDING: $48 MILLION
OUTSIDE GROUP SPENDING: $19 MILLION (40 percent) 

OUTSIDE GROUP BREAKDOWN:
PRO-ROMNEY: $15.8 MILLION OF $25.4 MILLION (62 percent)
PRO-OBAMA: $3.2 MILLION OF $22.9 MILLION (14 percent)

PENNSYLVANIA
OVERALL SPENDING: $19.3 MILLION
OUTSIDE GROUP SPENDING: $14.4 MILLION (75 percent)

OUTSIDE GROUP BREAKDOWN:
PRO-ROMNEY: $11.2 MILLION OF $11.2 MILLION (100 percent)
PRO-OBAMA: $3.2 MILLION OF $8.1 MILLION (40 percent)

NEVADA
OVERALL SPENDING: $38.6 MILLION
OUTSIDE GROUP SPENDING: $14.2 MILLION (37 percent) 

OUTSIDE GROUP BREAKDOWN:
PRO-ROMNEY: $13.3 MILLION OF $20.4 MILLION (65 percent)
PRO-OBAMA: $874,000 MILLION OF $18.2 MILLION (5 percent) 

WISCONSIN
OVERALL SPENDING: $14.5 MILLION
OUTSIDE GROUP SPENDING: $13.4 MILLION (92 percent) 

OUTSIDE GROUP BREAKDOWN:
PRO-ROMNEY: $10.2 MILLION OF $10.6 MILLION (96 percent)
PRO-OBAMA: $3.2 MILLION OF $3.9 MILLION (82 percent) 

NEW HAMPSHIRE
OVERALL SPENDING: $28.2 MILLION
OUTSIDE GROUP SPENDING: $11.9 MILLION (42 percent) 

OUTSIDE GROUP BREAKDOWN:
PRO-ROMNEY: $11.9 MILLION OF $14.1 MILLION (84 percent)
PRO-OBAMA: $0 OF $14 MILLION (0 percent) 

MICHIGAN
OVERALL SPENDING: $10 MILLION
OUTSIDE GROUP SPENDING: $10 MILLION (99.9 percent) 

OUTSIDE GROUP BREAKDOWN:
PRO-ROMNEY: $10 MILLION OF $10 MILLION (100 percent)
PRO-OBAMA: $10,000 OF $10,000 (100 percent)

Here’s the total of how every group is spending:

Obama $233,604,018
Crossroads GPS $59,977,352 (pro-Romney)
Romney $87,648,202
American Crossroads $48,441,218 (pro-Romney)
Americans for Prosperity $46,517,357 (pro-Romney)
Priorities USA $48,176,176 (pro-Obama)
Restore Our Future $44,408,615 (pro-Romney)
Republican National Committee $18,723,265 (pro-Romney)
Concerned Women for America $4,783,656 (pro-Romney)
America's Future Fund $4,580,908 (pro-Romney)
Americans Energy Alliance $3,201,354 (pro-Romney)
SEIU $2,497,313 (pro-Obama)
Planned Parenthood $1,447,734 (pro-Obama)
Priorities/League of Conservation Voters $979,048 (pro-Obama)
MoveOn.org $166,891 (pro-Obama)
Jill Stein (Green Party presidential candidate) $38,175

TOTAL $605.7 million

*** UPDATE *** The ACLU spending has been taken out of the "pro-Obama" category. The group contends it wasn't advocating for one candidate or the other. The ad it ran advocates for health-care benefits and abortion care for servicewomen who are victims of rape.

*** UPDATE 2 *** Numbers USA spending has also been taken out of the "pro-Romney category. The group is running ads that are anti-immigration, not explicitly support Romney or attacking Obama.