Year	Number
1960	6853
1961	7001
1962	7154
1963	7316
1964	7487
1965	7667
1966	7855
1967	8038
1968	8258
1969	8548
1970	8882
1971	9265
1972	9701
1973	10183
1974	10716
1975	11286
1976	11893
1977	12537
1978	13201
1979	13852
1980	14363
1981	14732
1982	15141
1983	15595
1984	15997
1985	16340
1986	16627
1987	16877
1988	17094
1989	17285
1990	17523
1991	17894
1992	18222
1993	18454
1994	18722
1995	19000
1996	19290
1997	19595
1998	19911
1999	20360
2000	20870
2001	21250
2002	21566
2003	21909
2004	22666
2005	23819
2006	24967
2007	26022
2008	26882
2009	27490
2010	27887
2011	28182
2012	28484
2013	28889
2014	29455
2015	30169
2016	30952
2017	31949
2018	33113
2019	34175
2020	34939
2021	35361
2022	35800
2023	36598