KNBC was the only one of L.A.’s Big Four O&Os to post demographic ratings gains in primetime during the May sweep, according to Nielsen’s just-released demo ratings report.

KNBC notched a 10% increase over last May to a 7.5 rating in the key adults 18-49 demo category in the Monday-Sunday primetime race during the sweep period (April 23-May 20) fueled in large part by May 14 farewell of “Seinfeld.”

KNBC also posted 12% year-to-year growth in the adults 18-34 (6.6) and adults 25-54 (8.5) categories. Fox O&O KTTV was tops overall in the Gen X index of adults 18-34 with a 7.5 rating, but that still marked a 21% decline from last May’s 9.5.

KTTV slipped 16% from last May to a 7.1 in adults 18-49 and eased 7% to a 7.4 in adults 25-54. KABC settled into third place in primetime for its second consecutive May sweep. The Alphabet O&O dropped 15% from year-to-year in adults 18-49 (4.9), slipped 12% in adults 18-34 (5.3) and dove 16% in adults 25-54.

KCBS was essentially unchanged from last year in adults 18-49 at a 3.1, but the Eye-owned outlet plunged 21% in adults 18-34 (1.9) and dropped 7% in adults 25-54 (3.8).

In the key local news races, demo ratings for most of the O&Os were down or flat from year-ago levels. KABC, reflecting the network’s primetime woes, notched the steepest declines in its evening and late newscasts. But at 4 p.m., KNBC and KABC were neck-and-neck, and essentially unchanged from last year, with 2.0 averages in adults 18-49 and 25-54.

At 5 p.m., KNBC led news rivals KABC and KCBS, but was still down 13% from last year to a 2.0 in adults 18-49, and down 20% to a 2.4 in adults 25-54. KABC fell 32% to a 1.5 in adults 18-49 and 30% to a 1.9 in adults 25-54. KCBS was flat with sub-1 demo ratings in the two categories. KTLA’s rerun of “Beverly Hills, 90210” led the timeslot with a 2.2 in adults 18-49.

At 6 p.m., Univision’s Spanish-lingo KMEX scored the news demo win among adults 18-49 with a 2.7, which still marked a 32% drop from last year’s 4.0. KNBC won the 25-54 crown with a 2.8, even with last year’s showing. In the 6:30 p.m. battle of the network newscasts, KMEX’s “Noticiero Univision” again ranked No. 1 in adults 18-49 with a 2.6, in spite of the 35% slide from last year’s 4.0.

KNBC’s “NBC Nightly News” was a close second with a 2.3 in adults 18-49, up 21% from year to year. KABC’s “World News Tonight” slipped 19% from last year in 18-49 to a 1.7. But it was Homer Simpson and family that won the timeslot, once again, with a 4.7 in adults 18-49, up 9% from last year’s first-place showing.

Among the four competing hourlong 10 p.m. newscasts, KTTV again paced the race by a wide margin, holding steady from last year with a 4.2 in adults 18-49, while its 3.7 in adults 25-54 was down 12% from the year-ago mark. Fourth-ranked KCOP jumped 55% over last year to a 1.4 in adults 18-49 to a 1.4 and a 50% spike to a 1.2 in adults 25-54.

Indie KCAL came in second to KTTV with a 50% gain to a 2.7 in adults 18-49 and a 24% increase to a 2.6 in adults 25-54. KTLA followed closely with a 4% gain from last year to a 2.5 in adults 18-49, and an 11% spike to a 3.0 in adults 25-54. KCAL’s newscast runs beyond 11 p.m. and into the red-hot “Jerry Springer” talkshow.In the hotly contested 7-8 p.m. prime access hour, Univision’s KMEX had a strong perf, averaging a 4.9 in adults 18-49 and a 5.8 in adults 18-34 for the telenovela “Sin Ti.” KTTV’s “Home Improvement” led the English-lingo field with a 3.9 in adults 18-49 and a 4.5 in adults 18-34. KTTV also was tops at 7:30 p.m. with “The Simpsons” commanding a 5.5 in adults 18-49 and a 6.7 in adults 18-34.