Year	Number
1971	334891
1972	348841
1973	408081
1974	436826
1975	469093
1976	494684
1977	517022
1983	462490
1984	448881
1985	453320
1986	450662
1987	441879
1988	433264
1991	434958
1993	493591
1994	496621
1995	495560
1996	489957
1999	476616
2000	476694
2001	481952
2002	467608
2003	470241
2004	479766
2005	485087
2006	486972
2007	482377
2008	476189
2009	472219
2010	484368
2011	484925
2012	484891
2013	652569
2014	656711
2015	668179
2016	651048
2017	661906