Year	Number of
1980	16011
1981	21925
1982	21579
1983	22753
1984	22792
1985	24438
1986	24702
1987	30571
1988	36908
1989	35687
1990	37905
1991	40580
1992	52552
1993	51675
1994	48601
1995	45310
1996	41739
1997	42062
1998	43723
1999	40345
2000	38661
2001	37197
2002	36092
2003	32064
2004	33414
2005	33747
2006	34311
2007	32407
2008	32193
2009	31844
2010	31073
2011	31241
2012	29760
2013	29731
2014	30008
2015	29833
2016	29733
2017	29840
2018	31421
2019	31764
2020	23755