Year	Number
1977	29.46956
1978	28.47888
1979	27.7827
1991	26.66773
1994	37.27042
1995	36.2809
1997	44.53891
1999	35.93639
2000	34.90296
2001	38.89617
2002	35.28227
2003	35.37191
2004	35.54274
2005	31.39262
2006	33.04696
2007	33.19107
2008	32.71282
2009	33.57812
2010	29.51018
2011	32.59666
2012	32.93793
2013	32.02921
2014	32.76808
2015	30.3322