It's a demo low for the telecast, as it still skews young and the audience drops by 24 percent.

Sunday's Bruno Mars-loving Grammy Awards took a dramatic ratings spill, fetching the smallest demo audience in the show's history.

The telecast, which ran a bloated three-and-a-half hours, was off by 24 percent from 2017 with adjusted numbers. With time zone adjustments taken into account, the telecast averaged 19.8 million viewers and a 5.9 rating among adults 18-49. The second stat marked a low for the show. Among total viewers, that number was down even more than overnight returns from Nielsen Media that it a 12.7 rating among households. It's the biggest drop for the Grammys since the 2013, the year after the show swelled following the death of Whitney Houston.

The 2017 overnight ratings for the Grammy Awards didn't paint the most accurate portrait of their year-over-year performance. The 16.0 rating among households, steady with 2016, ended up translating to a not-insignificant gain of 1 million viewers. Those Grammys were the best in two years, averaging just north of 26 million viewers and earning a 7.8 rating among adults 18-49.

CBS shifted the Grammys back to Sundays in 2017, a move that ultimately proved fruitful for the show. But, unlike the last few years, the 2018 Grammys happened rather early on the calendar — by a full two weeks. The Grammys last aired in January back in 2014.

On the bright side, CBS easily dominated all other original efforts for the night. The network also cites a 40 percent uptick in streaming on its All Access service, with sign-ups near an all-time high for a single day.

Criticism for the show, hosted by CBS' James Corden, has focused on political and social messaging in speeches and performances — but the 2018 Grammys were set up for a fall by the night's big nominees. Mars, Jay-Z and Kendrick Lamar just don't guarantee the kind of appointment viewing that 2017 competitors Beyonce and Adele do.

The least-watched Grammys were in 1995, where the 11.25 million viewers tied 1975 for the all-time low.