Year	% of total
1970	1.4858231620452396
1971	1.5597435797232786
1972	1.5833523275545485
1973	1.6022104187146267
1974	1.7403815551881991
1975	1.752298965861552
1976	1.7548953755942949
1977	1.810373522240695
1978	1.7704826997171976
1979	1.5860577354118923
1980	1.528732067906475
1981	1.5058884930147476
1982	1.5770110995872204
1983	1.611477817931924
1984	1.633790543762892
1985	1.6104308178529203
1986	1.5356021352456308
1987	1.584964884908593
1988	1.6431781506936933
1989	1.742264050853022
1990	1.33422281521014
1991	1.3568521031207599
1992	1.5099519560741248
1993	1.5214384508990317
1994	1.6107382550335572
1995	1.5696533682145193
1996	1.6183412002697235
1997	1.6937669376693765
1998	1.8018018018018018
1999	1.8206338503034392
2000	2.100271002710027
2001	1.9489247311827957
2002	1.9169329073482428
2003	2.0075282308657463
2004	2.2339027595269383
2005	2.214983713355049
2006	2.1739130434782608
2007	2.122015915119363
2008	2.1262002743484225