Year	Number
1960	6065
1961	6228
1962	6382
1963	6551
1964	6723
1965	6899
1966	7080
1967	7266
1968	7459
1969	7661
1970	7842
1971	8003
1972	8167
1973	8327
1974	8481
1975	8628
1976	8765
1977	8886
1978	8993
1979	9087
1980	9176
1981	9252
1982	9304
1983	9339
1984	9369
1985	9400
1986	9446
1987	9517
1988	9624
1989	9761
1990	9909
1991	10080
1992	10288
1993	10523
1994	10781
1995	11057
1996	11360
1997	11695
1998	12039
1999	12375
2000	12912
2001	13666
2002	14454
2003	15271
2004	16084
2005	16865
2006	17600
2007	18296
2008	18945
2009	19532
2010	19676
2011	19426
2012	19170
2013	18957
2014	18854
2015	18800
2016	18872
2017	19160
2018	19555
2019	20009
2020	20505
2021	20999
2022	21593
2023	22408