Year	Number
1960	19978
1961	20269
1962	20524
1963	20651
1964	20770
1965	20850
1966	20883
1967	20879
1968	20892
1969	20926
1970	20971
1971	21052
1972	21130
1973	21140
1974	21122
1975	21138
1976	21161
1977	21200
1978	21236
1979	21420
1980	21800
1981	22173
1982	22430
1983	22568
1984	22731
1985	22918
1986	23085
1987	23255
1988	23399
1989	23441
1990	23511
1991	23649
1992	23716
1993	23810
1994	24575
1995	24794
1996	24304
1997	24178
1998	24164
1999	24178
2000	24154
2001	24138
2002	24236
2003	24477
2004	24700
2005	24806
2006	25016
2007	25148
2008	25080
2009	25112
2010	25212
2011	25352
2012	25555
2013	25786
2014	26069
2015	26283
2016	26461
2017	26582
2018	26531
2019	26339
2020	26060
2021	25773
2022	25442