Year	Number
1994	17.52139
1995	17.50184
1996	16.50353
1997	16.3092
1998	16.70613
1999	17.05971
2000	17.21744
2001	17.38577
2002	17.58169
2003	18.08962
2004	19.12914
2005	18.39441
2006	17.2471
2007	15.91976
2008	14.93535
2009	14.37645
2010	14.47243
2011	14.55044
2012	14.31538
2013	14.05115
2014	14.16348
2015	13.82122
2016	13.38421
2017	13.8959
2018	13.88809