Fox's musical dramedy staple "Glee" aired its season finale Tuesday night, and viewers marked the occasion by not tuning in. Based on Nielsen overnights for the key 18-49 demo, the show lost 25% of its audience from a week earlier and registered its lowest number in series history with a 0.6 average.

TVbytheNumbers.com reports that Fox ended Tuesday prime time in sixth place among the broadcast networks, well behind even the CW, both in the demo and in total viewers. Part of the problem was Fox's new comedy improv series "Riot," which led out from "Glee" with a 0.5 average in 18-49 for the series premiere.

CBS won the night as its drama lineup aired their season finales: a 2.6 average in the 18-49 demo for the season finale of "NCIS," a 2.5 for the finale of "NCIS: Los Angeles" and a 1.9 for the finale of "Person of Interest." The three shows also produced the three best numbers of the night in total viewers: 16.77 million for "NCIS," 14.77 million for "NCIS: LA" and 10.83 million for "Person of Interest," just edging out the 10.77 million who turned out for NBC's "The Voice."

The NBC singing competition equaled the 2.5 average it had last week in adults 18-49, while back-to-back installments of NBC's "About a Boy" delivered a 1.7 for the first episode and a 1.5 for the season finale, equaling a series low. The season finale of "Chicago Fire" came in with a 1.9, the same as last week's episode and an improvement of 12% from the previous season finale.

ABC's season finale of "Marvel's Agents of SHIELD" delivered a 1.9, equaling the show's number from a week ago in the 18-49 demo. The season finale of "The Goldbergs" inched up 13% from last week's series low, managing a 1.4. "Trophy Wife's" series finale surged 29% from a series low a week ago to a 0.9 average, and "Celebrity Wife Swap" delivered another 0.9, matching last week's number.

The CW climbed ahead of Fox as two CW shows — "Supernatural" and the season finale of "The Originals" — both delivered 0.9 averages in 18-49, a 50% improvement from last week for "Originals" and a 13% uptick for "Supernatural." However, the report notes that the CW was pre-empted for baseball in some markets, meaning the network's numbers are subject to more than the usual adjustments.

For prime time overall, CBS had the best preliminary number in the 18-49 demo with a 2.3 average, followed by NBC (2.0 average), ABC (1.3), Univision (1.0), CW (0.9) and Fox (0.6). CBS was comfortably ahead in total viewers with 14.1 million, followed by NBC (8.1 million), ABC (3.8 million), Univision (2.6 million), CW (2.1 million) and Fox (1.6 million).