Year	Number
1960	17298
1961	17935
1962	18660
1963	19474
1964	20400
1965	21650
1966	23135
1967	24418
1968	25412
1969	26314
1970	27234
1971	28155
1972	29041
1973	29858
1974	30692
1975	31668
1976	32706
1977	33659
1978	34643
1979	35693
1980	36707
1981	37676
1982	38567
1983	39353
1984	40204
1985	41635
1986	43599
1987	45583
1988	47379
1989	49009
1990	50747
1991	52566
1992	54193
1993	55560
1994	56584
1995	57178
1996	57351
1997	57165
1998	56621
1999	55705
2000	54541
2001	53275
2002	51948
2003	50552
2004	49069
2005	47549
2006	46202
2007	45178
2008	44474
2009	44089
2010	44005
2011	44190
2012	44607
2013	45192
2014	46134
2015	47436
2016	48834
2017	50257
2018	51646
2019	52882
2020	53827
2021	54479
2022	54711
2023	54489