Year	Number
1970	39881
1972	34826
1973	32340
1975	33541
1976	28301
1978	33086
1979	37071
1980	35909
1981	33376
1982	38861
1985	50535
1986	48494
1987	49244
1989	50729
1990	52132
1991	51152
1992	43214
1993	40539
1994	43172
1995	35704
1996	24398
2011	2463
2012	2288
2013	6558
2014	15637
2015	15018
2016	13887