Year	Number
1984	14.04844
1985	17.85957
1986	15.26182
1988	15.64835
1989	14.59722
1992	14.95238
1993	13.67081
2000	14.44848
2001	11.51064
2002	10.02364
2003	9.82734
2004	9.27078
2005	9.92191
2007	10.11633
2008	10.54197
2009	9.68254
2010	9.26667
2011	9.18162
2012	8.19866
2013	12.41451
2014	8.48544
2015	8.31985
2016	7.9222