Year	Number
1971	16.37221
1972	17.37382
1973	18.49416
1974	19.37508
1975	21.35232
1983	24.12449
1984	26.3122
1985	24.29397
1986	26.78695
2003	28.89463
2004	28.02894
2013	25.09349
2014	23.87107