Year	Number
1972	8.25416
1973	8.58076
1994	15.58418
1995	14.86224
1997	11.75939
2000	13.28606
2001	11.9661
2002	15.05644
2003	17.43042
2004	12.5853
2005	22.74219
2006	29.04262
2011	20.7494
2015	17.7498
2017	13.87721