Year	Number
1971	9691
1972	12546
1973	14709
1974	16232
1975	17907
1976	20635
1977	22426
1978	27499
1979	29214
1980	35087
1981	41811
1982	49028
1983	52155
1984	53237
1985	55787
1986	56941
1987	48558
1988	44250
1989	43351
1990	45633
1991	49068
1992	42263
2001	63384
2002	64940
2003	66492
2005	75489
2006	79319
2008	79832
2009	89074
2011	120617
2012	122057
2016	114025
2017	132695