Year	Number
1960	2301
1961	2397
1962	2255
1963	2372
1964	2257
1965	2225
1966	2175
1967	2144
1968	2281
1969	2342
1970	2357
1971	2589
1972	2813
1973	3144
1974	3427
1975	3675
1976	3828
1977	3825
1978	4080
1979	4276
1980	4559
1981	4623
1982	4715
1983	4827
1984	4946
1985	5093
1986	5254
1987	5416
1988	5603
1989	5811
1990	6177
1991	6485
1992	6841
1993	7163
1994	7488
1995	7788
1996	8023
1997	8254
1998	8517
1999	8804
2000	9129
2001	9504
2002	9947
2003	10442
2004	10982
2005	11528
2006	12066
2007	12668
2008	13342
2009	14071
2010	14845
2011	15656
2012	16465
2013	17239
2014	17950
2015	18584
2016	19148
2017	19644
2018	20098
2019	20532
2020	20880
2021	21179
2022	21522
2023	21907