Nearly two-thirds of all U.S. households (64.5%) — 120.1 million people age two or older — watched at least one of the 2008 political conventions, according to a new analysis released Thursday by Nielsen. 

Viewership levels for the Democratic and Republican conventions were essentially even, with about half of all U.S. households watching each.  Overall, 15% of all homes tuned in to the Republican National Convention only, while 15.7% tuned in to just the Democratic National Convention.  Another 33.9% of all households tuned in to both conventions.

Homes that watched both conventions were likely to be older (age 65+) and better educated (32.3% had college degrees) than viewers who watched only one of the conventions. 

RNC-only households were usually bigger (four people or more), had higher incomes ($100,000+), and were more likely to be white, while DNC-only households were smaller (two people), less wealthy ($20,000 or less), and more likely to be African American.

One-fifth (21.2%) of DNC-only homes were headed by an African American, while 83.5% of RNC-only homes were headed someone who is white.

Similar percentages of African American and white viewers tuned in to both conventions (35.7% and 34.5%, respectively).  Among African Americans, 27.4% watched only the DNC, and only 8.1% watched only the RNC.  Meanwhile, 16.2% of white viewers watched the RNC only, and 13.6% watched the DNC only.

Read the full report — and stay tuned during the presidential debates for more Nielsen TV audience analyses.

Read coverage of Nielsen’s findings in the Baltimore Sun, The Boston Globe, Broadcasting & Cable, and Multichannel News.