Dome size	Responses	Total Visitors	Average	Domes	Projection	Percentage
United States	21m - up	2	595,000	297,500	16	4,760,000	21.8
	18 - 20.9	9	811,300	90,144	25	2,253,611	10.3
	15 - 17.9	11	720,551	65,504	53	3,471,745	15.9
	12 - 14.9	12	169,400	14,116	104	1,468,133	6.7
	9 - 11.9	22	248,078	11,276	324	3,653,512	16.7
	6 - 8.9	10	73,844	7,384	377	2,783,918	12.7
	1 - 5.9	4	20,692	5,173	664	3,434,872	15.7
	unknown				94
	TOTALS	(4%) 70	2,638,865		1657	21,825,793
International	21m - up	5	1,203,358	240,671	98	23,585,816	19.5
	18 - 20.9	9	1,637,872	181,985	122	22,202,264	18.3
	15 - 17.9	6	664,000	110,666	119	13,169,333	10.9
	12 - 14.9	3	226,000	75,333	206	15,518,666	12.8
	9 - 11.9	4	318,750	79,687	352	28,050,000	23.2
	6 - 8.9	12	201,678	16,806	764	12,840,166	10.6
	1 - 5.9	3	23,200	7,733	701	5,421,066	4.4
	unknown				248
	TOTALS	(2%) 42	4,274,858		2610	120,787,314

So the answer as of 1 January 2020 is:

Each year  142,613,107  people visit the 4,267 planetaria of the world.