Year	Number
1971	17.2
1985	20.43662
1998	23.42254
2000	21.47297
2001	25.28125
2002	25.67213
2003	21.8254
2004	26.36207
2005	27.87692
2006	26.78846
2007	19.91935
2008	22.39286
2014	39.45
2016	40.17778