Year	Number
1971	71951
1972	70083
1973	69865
1977	90057
1978	89857
1981	75776
1982	67916
1983	57192
1986	57090
1987	81857
1988	90257
1989	94127
1990	75517
1991	94417
2005	182303
2006	185286
2007	157714
2008	128289
2009	129423
2010	125412
2011	142268
2012	139453
2017	25815