There's no public info specificically available.
Some available from GEM's:
Total annual produciton for 2016 year: 10.3m cts, of that, 0.9m cts from their secondary deposit.
Auctioned 1.7m cts during 2016, yielded US$73m, US$43/ct.
The highest quarterly sales price, US$617/ct where they auctioned top quality rubies including a special ruby, "Rihno Ruby" 40.23ct.