Year	Number
1993	24.19218
1994	23.91825
1995	23.80929
1996	23.60979
1997	22.99856
1998	20.92426
1999	18.64171
2001	18.44599
2002	18.16731
2003	17.97911
2004	18.02434
2005	18.49414
2006	18.54232
2007	18.33579
2008	18.10194
2009	18.67636
2010	20.34604
2011	20.05662
2012	20.57732
2013	20.33179