As Google Trust Services has been available for a few weeks I thought it would be interesting to look at where it stands relative to other CAs based on its issuance volume.

#	CA Owner	Certificates			Pre-Certificates
		All	Unexpired	All	Unexpired
1	Internet Security Research Group	2,972,072,131	270,986,317	2,689,923,862	233,570,311
2	DigiCert	115,808,406	7,603,151	443,129,508	138,144,685
3	Sectigo	580,982,481	45,262,868	517,794,477	46,204,659
4	Google Trust Services LLC	13,909,548	467,650	120,070,013	21,232,287
5	Microsoft Corporation	17,567	170	32,448,453	16,959,805

For more on this methodology of counting see this post.