Year	Number
1975	5900000
1976	6500000
1977	7700000
1978	8400000
1979	9200000
1980	9700000
1981	11030000
1982	11830000
1983	12690000
1984	13610000
1985	14600000
1986	15660000
1987	16790000
1988	18000000
1989	19300000
1990	20700000
1991	22296491
1992	22848601
1993	23475147
1994	24097265
1995	25018894
1996	25914510
1997	28250447
1998	29246000
1999	30949000
2000	32070000
2001	33278200
2002	35500000
2003	36100000
2004	38500000
2005	40100000
2006	43900000
2007	45218214
2008	45539288
2009	45379601
2010	44915829
2011	44151461
2012	42168388
2013	40473148
2014	38212576
2015	35553328
2016	32276615
2017	31952072
2018	30108289
2019	27674128
2020	25892405
2021	23864124