The final ratings report will provide a more-detailed illustration, but based on the overnight numbers, it will definitely reveal a decline.

Update: The drop was, indeed, significant. Based on the fast nationals, the Grammys averaged a 10.0 adults 18-49 rating with 28.1 million viewers from 8-11PM (the actual telecast went about a half hour longer). The 2012 edition averaged nearly 40 million viewers.

Sunday’s telecast of the 55th Grammy Awards posted a 19.0 overnight metered market rating, which marks a steep decline from last year’s 25.2. That airing, which came the day after Whitney Houston’s sudden death, ranks as the second-most watched Grammy telecast to date.

According to TV Media Insights, this Sunday’s episode was, however, up from the 2011 number (17.9).