Year	% of total
1990	4.404486798789993
1991	4.52611589421236
1992	4.620460385901124
1993	4.780767533878941
1994	4.794507414947887
1995	5.02203841812867
1996	5.21426716994169
1997	5.431719978580458
1998	5.566146752699355
1999	5.799681016506566
2000	6.51989689562998
2001	6.543448016253158
2002	6.63336951037942
2003	6.651112152856481
2004	6.627293560506062
2005	6.559784739381758
2006	6.531703679227004
2007	6.562686050882528
2008	6.631708501131119