Nearly three months into the third quarter, traditional TV viewing is down 20%, according to recent analysis, due to the later start of the NFL season and lower results from summer shows including “America’s Got Talent.”

Bernstein Research says broadcast Nielsen-measured live program-plus same-day viewing among 18-49 viewers is down 30%.

Traditionally, the third week of September starts the new broadcast TV season -- part of the third-quarter period. Last year, the complete third quarter -- the July through September period -- witnessed broadcast TV viewing among 18- to-49-year-old viewers down 14% from the same period in 2018.

Cable TV network entertainment programming (non-kids programming networks) among 18-49 viewers is down 14% so far in this third-quarter period. Viewing of kids TV networks among the 2-11 age demographic is down 29%.

The top summer TV show -- NBC’s “America’s Got Talent” (Tuesday edition) is down 20% to 7.6 million Nielsen-measured viewers over a period of 15 weeks through September 6. “Talent”s Wednesday edition is off 36% to 5.5 million.

Just five of 39 summer shows have showed gains this summer:

ABC’s “Celebrity Family Feud” is up 1.2% to 5.3 million, while NBC’s “World of Dance” is 9% higher to 4.0 million, ABC’s “Holey Moley” is 13% higher to 3.6 million, ABC’s “Match Game" is 15% more to 3.2 million and CW’s “Burden of Truth” has grown 6% to 505,000.