Year	Number
1960	12795
1961	13118
1962	13549
1963	14072
1964	14671
1965	15315
1966	16025
1967	16792
1968	17555
1969	18279
1970	18937
1971	19547
1972	20108
1973	20623
1974	21156
1975	21727
1976	22325
1977	22948
1978	23589
1979	24236
1980	24967
1981	25750
1982	26464
1983	27109
1984	27656
1985	28065
1986	28360
1987	28566
1988	28701
1989	28801
1990	28826
1991	28803
1992	28793
1993	28826
1994	28938
1995	29068
1996	29145
1997	29236
1998	29364
1999	29497
2000	29652
2001	29834
2002	30092
2003	30289
2004	30389
2005	30519
2006	30644
2007	30836
2008	31220
2009	31793
2010	32338
2011	32840
2012	33508
2013	34318
2014	35241
2015	36247
2016	37251
2017	38349
2018	39589
2019	40974
2020	42543
2021	44192
2022	45840
2023	47415