MUMBAI: The highly anticipated second presidential debate between US President Barack Obama and his Republican rival Mitt Romney on 16 October has failed to attracted as many eyeballs as the first presidential debate that took place on 3 October.

According to viewership measurement agency Nielsen, the second presidential debate, which saw President Obama hitting hard at Romney, had an estimated 65.6 million viewership in US which is two million less than the viewership generated by the first debate.

The first presidential debate had 67.2 million viewers thereby becoming one of the top 10 most-watched presidential debates of the past 30 years. The town hall styled debate was broadcast across 12 US network and cable television channels.

However, the Obama-Romney debate despite being one of the most riveting encounters has failed to attract as many viewers as the vice-presidential encounter between Republican Sarah Palin and Democrat Joe Biden, which was watched by 69.9 million people and ranks as the second most-viewed debate ever.

According to Nielsen, the October 1980 encounter between Ronald Reagan and Jimmy Carter is the most watched presidential debate in US drawing 80.6 million viewers. The ratings agency has been providing data of presidential debates since 1976.

The three-way Bill Clinton, Ross Perot and George H.W. Bush matchup in 1992 with 69.9 million viewers, Gerald Ford and Jimmy Carter debate in 1976 with 69.7 million viewers and Michael Dukakis and Bush debate in 1988 with 67.3 million viewers are some of the other most watched debates in US.