Year	Number
1970	6.59016
1971	6.03279
1992	7.55918
1993	8.13211
1994	9.3469
1996	8.03833
1999	9.27982
2000	13.07018
2001	13.09474
2002	11.86019
2003	11.20734
2005	14.18996
2006	13.32288
2012	29.72844
2013	24.41481
2014	29.28483
2017	19.95756
2018	19.6773