Year	%
1978	22.91351
1979	21.80451
1980	21.61716
1981	13.89183
1982	15.26375
1983	17.81857
1985	24.77764
1988	28.51852
1989	32.94798
1990	36.8231
1991	36.72131
2015	96.51696