Year	Number
1971	353862
1972	377887
1973	410816
1974	449190
1975	388363
1976	382111
1977	411627
1978	409577
1979	411937
1980	422808
1988	453805
1990	506850
1991	563385
2008	403341
2009	331455
2011	290122
2012	196915
2014	185423
2016	177737