Year	Number
1960	16657
1961	17097
1962	17536
1963	17984
1964	18457
1965	18947
1966	19435
1967	19863
1968	20224
1969	20589
1970	20976
1971	21387
1972	21833
1973	22313
1974	22830
1975	23370
1976	23910
1977	24383
1978	24762
1979	25094
1980	25394
1981	25668
1982	25933
1983	26190
1984	26425
1985	26618
1986	26762
1987	26957
1988	27191
1989	27350
1990	27431
1991	27469
1992	27491
1993	27507
1994	27541
1995	27584
1996	27641
1997	27867
1998	28231
1999	28566
2000	28856
2001	29088
2002	29253
2003	29361
2004	29447
2005	29539
2006	29640
2007	29826
2008	30095
2009	30368
2010	30636
2011	30854
2012	30929
2013	30906
2014	30884
2015	30910
2016	30990
2017	31085
2018	31210
2019	31393
2020	31737
2021	32207
2022	32635
2023	33020