Year	Number
1980	96231
1981	75523
1982	71730
1983	76291
1984	54823
1986	175311
1987	196510
1988	147301
1989	162082
1990	182903
1991	168721
1992	156521
1993	177794
1994	172792
1995	183178
1996	185070
1998	194385
1999	205380
2000	247809
2001	217101
2002	226212
2003	260022
2004	267657
2005	295454
2006	294522
2007	304268
2008	326078
2009	305717
2010	358834
2011	328056
2012	335096
2013	350560
2014	358995
2015	382048
2016	405914
2017	458364