Year	% of total
1990	86.13829302770863
1991	85.80866401871727
1992	85.7044161153781
1993	85.72992707200267
1994	68.24067003477072
1995	68.67429978261345
1996	68.64412184203333
1997	69.10974231601764
1998	70.67255528520326
1999	71.05360021592122
2000	71.83934459587418
2001	71.33849087190883
2002	72.37959029999688
2003	73.04865763815926
2004	72.98415372050295
2005	73.80303218963914
2006	72.73988769965393
2007	73.40429107774096
2008	73.39554581634664