Year	Number
1960	16911
1961	17351
1962	17798
1963	18344
1964	18987
1965	19630
1966	20280
1967	20948
1968	21631
1969	22327
1970	23050
1971	23800
1972	24571
1973	25366
1974	26198
1975	26503
1976	26312
1977	26234
1978	26268
1979	26426
1980	26758
1981	27322
1982	28172
1983	28423
1984	28865
1985	30226
1986	31589
1987	32992
1988	34398
1989	35785
1990	31617
1991	27783
1992	29688
1993	31084
1994	31139
1995	31605
1996	32787
1997	35818
1998	40097
1999	42808
2000	44843
2001	46603
2002	48234
2003	48930
2004	49801
2005	52372
2006	55593
2007	58561
2008	61058
2009	63023
2010	64797
2011	67066
2012	68897
2013	69707
2014	70067
2015	70386
2016	71075
2017	71843
2018	72753
2019	73827
2020	74788
2021	75505
2022	76422
2023	78009