Year	% of total
1970	4.962030476982117
1971	4.895100906347202
1972	5.154044958044187
1973	5.113937223626435
1974	5.21865498617526
1975	4.916133215603711
1976	5.216898315642525
1977	4.985905931953354
1978	5.376148659676639
1979	5.577717732952476
1980	5.1366712456168955
1981	5.032819224300197
1982	5.093263233522743
1983	4.859459181098601
1984	4.406880996750022
1985	4.526015461317327
1986	5.051509750066829
1987	5.140401293836132
1988	5.46816500039662
1989	5.563086567627686
1990	1.1235955056179776
1991	1.1111111111111112
1992	1.098901098901099
1993	1.0869565217391304
1994	1.0752688172043012
1995	1.0526315789473684
1996	0.9615384615384616
1997	0.8849557522123894
1998	0.819672131147541
1999	0.7575757575757576
2000	0.7092198581560284
2001	0.6535947712418301
2002	0.684931506849315
2003	0.6622516556291391
2004	0.6578947368421052
2005	0.6622516556291391
2006	0.628930817610063
2007	0.6172839506172839
2008	0.6097560975609756