Year	Number
1972	13.58576
1973	13.88499
1974	14.04277
1975	13.8265
1976	12.53199
1977	13.61812
1978	13.66542
1979	12.02703
1980	12.11573
1992	13.40997
1993	12.90293
1994	12.58101
1995	12.541
2013	7.73805
2014	8.05511
2015	8.36258
2016	8.29763
2017	8.35604
2018	8.56276