Sunday Night Football ratings suffered a rare decline in Week 13.

Chargers-Steelers earned a 10.5 rating and 17.83 million viewers on NBC’s Sunday Night Football last weekend, down 7% in ratings and 9% in viewership from last year (Eagles-Seahawks: 11.3, 19.7M) but up 3% and a fraction of a percent, respectively, from 2016 (Panthers-Seahawks: 10.2, 17.75M).

Los Angeles’ win posted the third-smallest audience on NBC this season, ahead of Bengals-Chiefs in Week 7 (16.0M) and Saints-Vikings opposite the World Series in Week 8 (14.1M).

It was just the third NBC game since Week 1 to decline (13 telecasts).

For the first time in more than two years — since Week 6 of the 2016 season — NBC did not air the top primetime game of the week. That distinction went to FOX and NFL Network, which combined for a 12.5 and 21.3 million for Saints-Cowboys Thursday night.

SNF scored a 5.4 rating in adults 18-49, down 16% from last year (6.4) and down 11% from 2016 (6.1). It was the lowest for the series in Week 13 since 2005, the last year ESPN held rights (3.3).

Ratings in adults 18-34 were also the lowest since 2005 (3.9, -24%). In adults 25-54, ratings were the lowest since 2008 (6.7, -11%).

Pittsburgh led all markets Sunday night with a 45.9 rating. San Diego, the former home of the Chargers, ranked second with a 22.8. New Orleans (18.4), Richmond (17.8) and Albuquerque (16.8) rounded out the top five. Los Angeles did not crack the top ten, ranking 18th with a 12.9. Keep in mind that due to its size, the 12.9 in Los Angeles still equals significantly more television homes (appx. 681K) than the 45.9 in Pittsburgh (appx. 509K) or the 22.8 in San Diego (appx. 225K).

The full list of Week 13 NFL ratings is available here.

[Numbers from Nielsen via ShowBuzz Daily 12.4; additional info from NBC Sports PR/Twitter 12.3]