Year	Number
1960	21829
1961	22611
1962	23410
1963	24211
1964	25018
1965	25849
1966	26706
1967	27569
1968	28437
1969	29319
1970	30210
1971	31088
1972	31954
1973	32814
1974	33673
1975	34514
1976	35336
1977	36156
1978	36970
1979	37765
1980	38553
1981	39391
1982	40269
1983	41132
1984	41980
1985	42812
1986	43617
1987	44392
1988	45144
1989	45875
1990	46580
1991	47310
1992	47900
1993	48474
1994	49020
1995	49529
1996	49992
1997	50396
1998	50759
1999	51096
2000	51428
2001	51761
2002	52089
2003	52350
2004	52538
2005	52696
2006	52830
2007	52967
2008	53150
2009	53348
2010	53518
2011	53651
2012	53776
2013	53890
2014	54053
2015	54267
2016	54436
2017	54657
2018	54955
2019	55205
2020	55488
2021	55768
2022	56002
2023	56307