Year	Number
1971	18.51217
1972	16.05509
1983	9.15898
1985	9.45174
1992	15.83241
1996	7.81195
1999	12.67489
2000	13.15351
2001	14.16831
2002	12.98374
2003	12.8662
2004	7.76553
2005	7.9816
2006	8.07703
2007	8.58917
2008	8.43296
2009	8.21562
2010	8.01335
2011	8.33241
2012	7.46494
2014	4.98637