Year	Number
1960	16029
1961	16202
1962	16390
1963	16591
1964	16811
1965	17047
1966	17292
1967	17557
1968	17837
1969	18133
1970	18451
1971	18797
1972	19167
1973	19561
1974	20001
1975	20499
1976	21046
1977	21649
1978	22298
1979	22983
1980	23697
1981	24435
1982	25213
1983	26037
1984	26905
1985	27817
1986	28779
1987	29792
1988	30860
1989	31942
1990	33039
1991	31733
1992	30351
1993	31638
1994	32960
1995	34878
1996	36711
1997	37764
1998	39022
1999	40282
2000	41531
2001	43251
2002	45196
2003	47373
2004	49579
2005	51369
2006	53058
2007	54840
2008	57054
2009	59343
2010	61593
2011	63907
2012	66142
2013	68207
2014	70116
2015	71709
2016	73109
2017	74746
2018	76680
2019	78768
2020	80907
2021	82929
2022	84831
2023	87000