Year	Number
1971	7589
1972	8127
1973	9139
1974	10817
1975	11519
1976	12437
1977	14153
1978	15514
1979	17070
1980	18251
1981	19429
1982	20328
1983	21481
1984	23871
1985	25390
1986	26475
1987	27466
1988	29052
1989	29725
1990	31030
1991	32057
1992	33405
1993	38504
1994	40495
1995	35905
1996	46820
1997	39260
1998	40691
1999	41848
2004	46697
2005	48195
2006	48607
2007	49777
2013	52746
2014	46884
2015	45452
2016	47630
2017	47402
2018	47971
2019	49342
2020	50103
2021	52993