Year	Number
1971	42.56625
1972	43.50178
1973	40.90431
1984	41.53049
1987	36.62732
1992	40.20943
1993	41.53712
1994	44.08473
1995	44.7528
1998	40.43316
1999	26.01515
2002	34.33504
2007	38.29543
2008	39.02034
2009	37.32547
2010	37.0131
2011	37.37094
2012	34.74758
2013	37.06925
2014	35.31936
2015	33.19793