Year	Number
1971	8803
1972	8997
1973	10119
1974	11953
1975	12682
1976	13167
1977	14958
1978	16128
1979	17401
1980	20529
1981	23420
1982	25273
1983	27618
1984	31474
1985	39369
1986	48938
1987	57937
1988	67271
1989	78627
1990	84233
1991	91727
1992	97170
1993	107024
1994	116033
1999	160096
2000	174501
2001	181882
2003	218493
2004	246162
2005	272980
2006	296747
2007	327799
2008	397933
2009	441781
2010	511585
2011	578291
2012	648956
2013	732715
2014	813654
2015	935561
2016	1028133
2017	1132340
2018	1252441