Year	Number
1971	20046
1973	20374
1981	30316
1982	31884
1983	34859
1984	35479
1985	35878
1986	35080
1987	36754
1988	37292
1989	36930
1990	36533
1991	40820
1994	37616
1995	37827
1997	43205
1998	43282
1999	44542
2000	44852
2001	45914
2002	48476
2003	49293
2004	50186
2005	50654
2006	51212
2007	48736
2008	48223
2009	46658
2010	46905
2011	45408
2012	45296
2013	44840
2014	44895
2015	44292
2016	44884
2017	46149
2018	46157
2019	51578
2020	51486
2021	44875
2022	45148