Year	Number
1977	1.7763962848960195
1978	1.5020541596079366
1979	2.3573993241198883
1980	2.2488672608439257
1981	3.6701739619651677
1982	2.3065483418058847
1983	2.4068552110570747
1984	2.81865577995776
1985	2.2049183744595493
1986	2.3373398283922473
1987	3.275743828100456
1988	3.8610382094013427
1989	4.007921905656216
1990	3.410203706789559
1991	3.8380729837620513
1992	3.424035318998988
1993	4.4564871108694115
1994	9.626483080766711