Year	Number
1992	11.73688
1994	12.67262
1995	11.79247
2000	12.05507
2001	13.09381
2002	13.84181
2003	14.68757
2004	14.33616
2005	14.40707
2006	13.98137
2007	13.79568
2008	13.65694
2009	13.92617
2012	14.41403
2013	11.02496
2015	10.50924
2016	10.28417
2017	9.85926