Year	Number
1960	9771
1961	10039
1962	10363
1963	10703
1964	11059
1965	11434
1966	11802
1967	12161
1968	12541
1969	12944
1970	13284
1971	13531
1972	13748
1973	13964
1974	14193
1975	14466
1976	14774
1977	15079
1978	15379
1979	15682
1980	16093
1981	16654
1982	17275
1983	17930
1984	18618
1985	19339
1986	20090
1987	20868
1988	21679
1989	22526
1990	23281
1991	23874
1992	24422
1993	24976
1994	25539
1995	26103
1996	26663
1997	27209
1998	27730
1999	28234
2000	28572
2001	28649
2002	28608
2003	28521
2004	28392
2005	28230
2006	28044
2007	27842
2008	27626
2009	27406
2010	27189
2011	26951
2012	26678
2013	26369
2014	26017
2015	25629
2016	25208
2017	24762
2018	24290
2019	23786
2020	23268
2021	22746
2022	22399
2023	22230