Year	% of total
1970	4.410572541011688
1971	4.659644975253627
1972	4.716947121727743
1973	4.752490930961419
1974	4.4772928044297196
1975	4.500413496881231
1976	4.5581925490219986
1977	4.429985514520019
1978	4.494564479160651
1979	4.952804978482681
1980	5.451064020782264
1981	5.5197209177305755
1982	5.269040580365144
1983	6.020118717780897
1984	6.000528175598157
1985	6.0421456970943765
1986	6.677375290554885
1987	7.164284993699321
1988	7.059552163755768
1989	6.187926654456992
1990	11.224489795918368
1991	13.701431492842536
1992	12.734082397003746
1993	11.694915254237289
1994	11.76470588235294
1995	13.345864661654137
1996	13.766730401529637
1997	12.852112676056338
1998	13.19073083778966
1999	11.710323574730355
2000	11.42433234421365
2001	11.617647058823529
2002	11.688311688311687
2003	11.279229711141678
2004	11.864406779661017
2005	11.637347767253045
2006	11.662198391420912
2007	11.631016042780749
2008	11.671087533156498