Year	Number
1981	21346
1982	29985
1983	31619
1984	33891
1985	30701
1986	35185
1987	39333
1988	39618
1989	42788
1990	48441
1991	52981
1992	63545
1993	48776
1994	76265
1995	61291
1999	87331
2000	104363
2001	142590
2002	154210
2003	156798
2004	159466
2005	174121
2006	206947
2007	240690
2008	241938
2009	262627
2010	304933
2011	353682
2012	305415
2013	359016
2014	352156
2015	426008
2016	463859
2017	449478