The news network's coverage of the 10 candidates slides by more than 40 percent over the first debate of the primary cycle in late June.

The second Democratic presidential primary debate didn't draw nearly as big an audience as the first.

CNN's coverage of Tuesday's debate — the first of two, featuring 10 candidates each night — drew 8.69 million viewers (including CNN en Español). That's down a sizable 43 percent from the opening debate on June 26, though it's not an entirely apples-to-apples comparison, since the latter aired across three networks: NBC, MSNBC and Telemundo. CNN's audience Tuesday is a tick higher than NBC's share (8.68 million) of the June 26 total.

The first round of debates among the Democratic hopefuls drew 15.26 million viewers for night one and 18.1 million for night two — the latter figure a record for a Democratic primary debate.

CNN's biggest audience for a Democratic primary debate is 15.46 million. That came in October 2015; it was the party's first debate of the 2016 election cycle and featured a field of just five candidates, rather than the 20 who will be onstage Tuesday and Wednesday nights.

The decline for Tuesday's debate compared to the June 26-27 telecasts mirror that of the second Democratic primary face-off in 2015. After CNN drew 15.46 million people in October 2015, the next forum for Democratic hopefuls on CBS a month later fell to 8.5 million viewers.

The two-hour telecast (excluding 25 minutes of candidate introductions and a review of the rules) also drew 2.53 million viewers in the key news demographic of adults 25-54. It's the second most-watched Democratic primary debate in CNN's history, behind the October 2015 telecast.

Live streams of the debate on CNN's digital properties averaged 516,000 viewers, the network says, with an average viewing length of 75 minutes.

The record audience for either major party's primary debates remains 24 million for the first Republican debate of the 2016 cycle in August 2015.