Year	Number
1993	12.69291
1994	12.25859
1995	13.62806
1996	9.97091
1997	11.47528
1998	10.84407
1999	10.31907
2000	9.93348
2001	9.59231
2002	9.14314
2003	8.61624
2004	8.12566
2005	7.71402
2006	7.96273
2007	8.09305
2013	7.34704
2014	7.83545
2015	8.13518
2016	7.69151
2017	7.80161