Year	% of total
1970	67.65776190496301
1971	66.81313596848835
1972	66.56634032954753
1973	67.3025263128609
1974	64.13251213280869
1975	64.67453055641538
1976	64.93588735937082
1977	65.9203950437704
1978	64.04624914670028
1979	63.622856786786805
1980	64.21324273616872
1981	61.1176879323617
1982	63.10923612598849
1983	61.942541816074396
1984	61.606039892764755
1985	59.82212960368306
1986	60.0797392132599
1987	55.87489853328108
1988	55.811041566992245
1989	57.629993400009404
1990	60.94377510040161
1991	61.224489795918366
1992	61.105815061963774
1993	61.18848653667596
1994	59.943714821763606
1995	57.99289520426287
1996	56.433978132884775
1997	55.7919621749409
1998	55.58002936857562
1999	52.86439448875997
2000	51.46648044692738
2001	51.19291070211316
2002	51.415404871626066
2003	53.32512315270937
2004	52.496954933008524
2005	53.991958644457206
2006	49.30875576036866
2007	50.20811654526535
2008	56.470588235294116