About a fifth of U.S. households watching television Wednesday saw Barack ObamaBarack Hussein ObamaNew Hampshire Rep. Kuster endorses Buttigieg Overnight Defense: Foreign policy takes center stage at Democratic debate | House delivers impeachment articles to Senate | Dems vow to force new vote on Trump's border wall Ray LaHood backs Biden for president MORE's 30-minute commercial, according to Nielsen's ratings.

The ad got a 21.7 rating in the top 56 local television markets. The rating takes into account only those homes watching television at the time.

The rating is higher than Ross Perot's extended commercial in 1996, which received a 16.8 rating. The ratings for the three presidential debates ranged from about 35 to 42.