Year	Number
1970	9448300
1971	9504500
1973	9764900
1974	9254900
1975	9244700
1976	9562900
1977	9915900
1978	10183700
1979	10653400
1980	10704900
1981	10270100
1982	10335800
1983	10758700
1984	11404000
1985	11897900
1986	12677000
1987	13244800
1988	13880900
1989	14021100
1990	14583900
1991	14360900
1992	14918800
1993	15986200
1994	17218900
1995	18008200
1996	18953600
1997	19546600
1998	19653200
1999	20736600.000976562
2000	22008658
2001	22264220
2002	20817389
2003	21282617
2004	23752616
2005	24215712
2006	24829383
2007	26016011
2008	25498093
2009	26122523
2010	30222074.540528342
2011	31203707.09518173
2012	31434525.58607934
2013	32160518.88217208
2014	33026724.97907692
2015	34030586
2016	35337714
2017	36299460.058000006
2018	37405640.24838591
2019	38082933.01012836
2020	20098778.56340001
2021	24054588.846