So now that the major broadcast networks have announced which new scripted shows will grace their fall schedules, what are their prospects?

If the past four years are any indication, about 33% of scripted series will make it to a second season, 25% to a third season and 20% to a fourth.

According to research by Variety and Variety Insight, of the 135 primetime scripted series ordered by ABC, CBS, Fox and NBC since the May 2009 upfronts, exactly one-third — 45 — earned season-two renewals (with one, NBC’s “Hannibal,” legitimately awaiting resolution of its fate).

Depending on your perspective, that doesn’t seem like a bad batting average — and it’s fairly consistent across the networks, no matter how many shows they ordered. Fairing the best over the past four years were Fox series (10 for 27, 37.0%), while the worst were CBS freshmen (8 for 26, 30.8%), but the percentage difference is fairly negligible. The success rate for ABC (14 for 40, 35.0%) and NBC (13.5 for 42, 33.7%), which ordered the most shows, fell in range.

The best single season for any network since 2009 was ABC’s 2011-12, when it greenlit 12 new shows and renewed six for sophomore seasons: “Don’t Trust the B,” “Last Man Standing,” “Once Upon a Time,” “Revenge,” “Scandal” and “Suburgatory.” Five of those programs remain alive today, with “Scandal” emerging as a bonafide hit and “Once Upon a Time” strong enough to spawn a 2013-14 spinoff, “Once Upon a Time in Wonderland.”

This past season appears to have been pretty rough for new skeins on NBC, with only two survivors out of 12, “Chicago Fire” and “Revolution” — though “Chicago Fire” also generated a spinoff in “Chicago PD,” and “Hannibal” could still make things respectable. The real backbreaker for the Peacock was 2010-11, when 12 freshmen took to the air, one (“Harry’s Law”) made it to season two and none to season three.

ABC has more new 2011-12 series alive today than the other three networks combined. The lone Fox survivor that debuted that season is “New Girl,” while for NBC it’s (appropriately) “Grimm.” Of the seven CBS shows that premiered in 2011-12, only “Person of Interest” is on its 2013-14 schedule, though “Unforgettable” rose from the dead to earn a second season as a summer series beginning in late July, nearly 18 months after it was supposedly canceled.

In total, 27.6% of the 39 2011-12 premieres appear three seasons later on 2013-14 schedules for the big four networks. An almost identical 26.9% of 2010-11 premieres and 27.5% of 2009-10 premieres reached at least season three.

What about four seasons? The recent figures show more variance. While 24.1% of 2009-10 shows made it to a fourth season, merely 13.9% of shows born the following year did so, for an overall total of 12 out of 65 —18.5%.

Eliminating “Cougar Town,” which migrated to TBS after three years on ABC, the shows since 2009 that have gone at least four years on the big four are the Alphabet net’s “Modern Family” and “The Middle,” CBS’ “Blue Bloods,” “The Good Wife,” “Hawaii Five-0,” “Mike & Molly” and “NCIS: Los Angeles,” Fox’s  “Bob’s Burgers,” “The Cleveland Show” and “Raising Hope” and NBC’s “Community” and “Parenthood.”