Four weeks into the broadcast prime-time summer season, ABC has 12 of the top 20 shows, with NBC “America’s Got Talent” maintaining its position as the No. 1 summer series.

The perennial summer leader “Talent” is earning an average 8.8 million this year, looking at Nielsen’s live program-plus-seven days of time-shifted viewing metric from May 27 through June 27.

For "America's Got Talent," the main Tuesday airings this year are down 9% to 6.6 million, for Nielsen’s-live plus-same-day viewers. Many other returning summer shows have also seen declining viewing.

This year, “Talent” -- from June 1 through July 6 -- has pulled in $32 million in national TV ad spending getting to a total 2.3 billion impressions, according to estimates from iSpot.tv. YoY produced $41.4 million and 3.2 billion impressions.

Completing the top 20 this year -- after ABC’s 12 prime-time shows- -- NBC had six and CBS had two.

ABC’s “The Good Doctor” (7.6 million) and “Grey’s Anatomy” (7.1 million) were its two best results. CBS saw its best with “The United States of Al,” at 4.7 million viewers, and “Clarice” with 3.9 million viewers.

After “America’s Got Talent,” NBC’s New Amsterdam” was at 7.1 million and “Law & Order: SVU” had 6.8 million viewers.

Among the top five English-language broadcast networks, the average prime-time show is at 3.2 million viewers this year.

Over the month-long period this year, iSpot.tv says there were 79.8 billion impressions, amassing $391.5 million in national TV advertising spending among all broadcast and cable networks.