USCIS h1-b data hub
https://www.uscis.gov/h-1b-data-hub
Better than myvisajobs/h1bdata.info, as the latter sites just give you info on LCAs.
Number of employers and Number of LLCs decreased by 60% in 2019.
year ia id ca cd ia+id ca+cd #employers #LLC
---- ----- ---------- --------- ------ ---------- ---------------------------
2019 33366 15345 43268 9706 48711 52974 21087 4757
2018 87889 28181 247072 33165 116070 280237 48977 11283
2017 96166 14518 277229 15338 110684 292567 44199 9563
2016 105092