American Theatre magazine covers the vast world of U.S. professional not-for-profit theaters – numbering more than 1,800. Its list of the 2017-18 season's most-produced plays and playwrights is out, and nearly all have played Philly recently or are about to, strong evidence of the region's vitality. Among the names are Philadelphia-linked playwrights Quiara Alegría Hudes and Aaron Posner.

The most-produced living playwright among these theaters nationally is now Judith Gunderson, whose I and You graced People's Light last spring. Her Exit, Pursued by a Bear comes to Jenkintown's Pulley & Buttonhole Theatre in May.

No. 4 is Lisa Kron, whose Fun Home was at the Kimmel's Forrest Theatre in June and whose 2.5 Minute Ride is about to ride away at Theatre Horizon in Norristown, Oct. 6-29.

Ayad Akhtar (7) has been here in Disgraced at Philadelphia Theatre Company in 2015 and Invisible Hand at Theatre Exile last year.

West Philly's Quiara Alegría Hudés (her Pulitzer-winning Water by the Spoonful ran at South Camden Theatre Company in December) came in at No.  8, ahead of Tennessee Williams (11), ha ha ha.

August Wilson (12) checked in at the Arden in a fine 2016 Two Trains Running. MacArthur-winner Branden Jacobs-Jenkins is at No. 13; his Octoroon scorched the Wilma stage last year.

Lucas Hnath (15) dominated South Broad Street with two plays in quick succession in May 2016: The Christians (an excellent play I saw at Edinburgh Fringe) at the Wilma, then Hillary and Clinton at PTC.

And Aaron Posner, cofounder of the Arden, is at No. 16, ahead of Eugene O'Neill (17) and Oscar Wilde (20).

The No. 1 most-produced play among  nonprofit theaters nationally is the stage adaptation of Shakespeare in Love, with 15 productions. Why hasn't it come here yet?

At No. 2 is Kron's Fun Home. Dominique Morisseau's Skeleton Crew (3), I'm excited to say, runs at People's Light on June 13-July 8. The Curious Incident of the Dog in the Night-Time (4) played this winter at Kimmel's Academy of Music. No.  6 is The Humans by Steven Karam, coming to the Walnut Street Theatre Jan. 16-March 4.