Year	% of total
1970	2.7006190113439508
1971	2.6897259587162017
1972	2.2519096453764402
1973	2.8309543720657
1974	3.052921040629333
1975	2.964031634849739
1976	2.7634261447816324
1977	1.587446920638183
1978	2.21783573237633
1979	1.5751142258780608
1980	2.837450536025718
1981	2.6341729347930642
1982	2.064770520011035
1983	1.537253504572177
1984	1.1375259232177246
1985	1.3037586336587998
1986	1.224778706758884
1987	1.1827645120784844
1988	1.6537380181166221
1989	2.166115785851826