Year	Number
1960	2221
1961	2245
1962	2272
1963	2298
1964	2327
1965	2365
1966	2411
1967	2459
1968	2507
1969	2555
1970	2675
1971	2897
1972	3160
1973	3428
1974	3710
1975	3998
1976	4283
1977	4571
1978	4853
1979	5141
1980	5452
1981	5784
1982	6128
1983	6484
1984	6846
1985	7211
1986	7576
1987	7942
1988	8310
1989	8694
1990	9157
1991	9696
1992	10251
1993	10809
1994	11363
1995	11910
1996	12453
1997	12986
1998	13510
1999	14028
2000	14548
2001	15086
2002	15642
2003	16207
2004	16783
2005	17374
2006	17976
2007	18592
2008	19205
2009	19807
2010	20397
2011	20980
2012	21564
2013	22154
2014	22740
2015	23313
2016	23863
2017	24396
2018	24916
2019	25421
2020	25928
2021	26268
2022	26440
2023	26614