Year	Number
1970	216965
1971	220332.6
1972	252950.2
1973	276280.5
1974	308758.9
1975	369069
1976	404961.9
1977	443796
1978	493158.3
1979	559897.5
1980	604516.6
1981	658043.3
1982	713073.9
1983	765635.9
1984	827504
1985	892444.8
1986	941220.8
1987	1013783
1988	1102749
1989	1114731
1990	1124130
1991	1134194
1992	1124087
1993	1209143
1994	1311163
1995	1359929
1996	1373295
1997	1436867
1998	1388291
1999	1343727
2000	1397212
2001	1407501
2002	1432704
2003	1445511
2004	1451870
2005	1415347
2006	1388649
2007	1314765
2008	1382219
2009	1444270
2010	1536401
2011	1584171
2012	1601315
2013	1628956
2014	1719181
2015	1814942
2016	1878834
2017	1973700
2018	2029942