Over $100 million spent in campaign ads so far

NBC NATIONAL NEWS — About $108 million has been spent so far on television ads in the presidential general election campaign according to an analysis by NBC News and SMG Delta.

Only 16 states have seen campaign television ad spending since the Republican nomination fight ended; the lion's share has been concentrated in 10 battleground states, including Florida, Virginia, or Ohio.

The Obama campaign has accounted for 40 percent of all TV ad spending in the general election contest.

But outside conservative groups, not including the Romney campaign, have combined to outspend the Obama campaign by about $8 million.