Year	Number
1960	6074
1961	6260
1962	6448
1963	6640
1964	6838
1965	7044
1966	7254
1967	7473
1968	7703
1969	7942
1970	8186
1971	8440
1972	8708
1973	8989
1974	9437
1975	10055
1976	10697
1977	11368
1978	12061
1979	12767
1980	13479
1981	14173
1982	14844
1983	15558
1984	16174
1985	16689
1986	17296
1987	18006
1988	18794
1989	19623
1990	20486
1991	21381
1992	22205
1993	22735
1994	23114
1995	23668
1996	24361
1997	25074
1998	25797
1999	26526
2000	27233
2001	27919
2002	28581
2003	28840
2004	28757
2005	28749
2006	28811
2007	28940
2008	29146
2009	29430
2010	29759
2011	30125
2012	30507
2013	30765
2014	30815
2015	30868
2016	31092
2017	31438
2018	31899
2019	32530
2020	33239
2021	33921
2022	34731
2023	35863