NEW YORK — An estimated 24.6 million television viewers watched President Donald Trump’s second inauguration, the smallest audience for the quadrennial ceremony since Barack Obama’s second inauguration in 2013.

The Nielsen Co. said viewership was down from Joe Biden’s 2021 inauguration, which reached 33.8 million, and Trump’s first move into the White House, seen by 30.6 million in 2017.

Inauguration viewership has varied widely over the past half-century, from a high of 41.8 million when Ronald Reagan came into office in 1981 to a low of 15.5 million for the start of George W. Bush’s second term in 2004.

The length of Trump’s inauguration coverage may have hurt him in bragging rights. The 24.6 million figure represents the average number of people tuning in to coverage on one of 15 networks between 10:30 a.m. and 7:30 p.m. Eastern time. In past years, the coverage didn’t go on for so long, which meant the averages were likely higher because people tune away as the day goes on.