Year	% of total
1990	4.86098002879177
1991	4.924393076201214
1992	4.958836909041367
1993	5.047985083233886
1994	4.523679017690195
1995	4.680719257022729
1996	4.850963622453425
1997	5.019978576490056
1998	5.1167089050491565
1999	5.296388554229814
2000	5.974795982025783
2001	6.099274230474419
2002	6.197636298704744
2003	6.163246181261366
2004	6.166246386274111
2005	6.127073117475985
2006	6.133828301308354
2007	6.063171779121878
2008	6.090325845077491