Year	% of total
1990	65.16361571211492
1991	64.93921832256751
1992	64.45329858808148
1993	64.31264974028132
1994	63.55083607342441
1995	62.798339980682776
1996	62.25028260323368
1997	62.746875828572904
1998	65.15866768552935
1999	68.31160066558424
2000	67.8574079161436
2001	68.8408543230314
2002	69.13347597179288
2003	67.3675968150454
2004	68.28626384960256
2005	67.3529192615081
2006	69.2108817590012
2007	70.25868168659918
2008	71.42742038442701