1,100 games completed.
http://computerchess.org.uk/ccrl/404FRC ... _pure.html
Hiarcs 13.1 previously had a rating of 2995 on the pure list database. Hiarcs 13.2 has a rating of 3023 on the pure list, so that is a +28 ELO gain. This is how I prefer to measure the improvement of an engine.
In terms of the bigger complete database, Hiarcs 13.2 at 3023 compares to Hiarcs 13.1 at 3000, so a +23 ELO gain
So take your pick, improvement is approximately in the range 20-30 ELO.