Year	Number
1960	22555
1961	23176
1962	23755
1963	24336
1964	24974
1965	25614
1966	26095
1967	26626
1968	27153
1969	27678
1970	28193
1971	27932
1972	27631
1973	27338
1974	27050
1975	26763
1976	26775
1977	26782
1978	26792
1979	26810
1980	27184
1981	27342
1982	27518
1983	27737
1984	27963
1985	28190
1986	28414
1987	28621
1988	28838
1989	29051
1990	29261
1991	29074
1992	28822
1993	28939
1994	29109
1995	29288
1996	29444
1997	29583
1998	29762
1999	29890
2000	30126
2001	30434
2002	30625
2003	30832
2004	31042
2005	31239
2006	31408
2007	31567
2008	31740
2009	31921
2010	31673
2011	31399
2012	31513
2013	31606
2014	31669
2015	31722
2016	31368
2017	30993
2018	30975
2019	30926
2020	30872
2021	30759
2022	30645
2023	30585