Year	% of total
1990	50.67294751009421
1991	49.59128065395095
1992	44.87840825350037
1993	44.51802796173657
1994	43.46210995542348
1995	44.50867052023121
1996	44.37229437229438
1997	43.89009399855387
1998	43.32365747460087
1999	42.01362604087812
2000	39.14100486223663
2001	38.17878028404344
2002	38.074957410562185
2003	38.062283737024224
2004	38.21209465381244
2005	36.162361623616235
2006	36.58536585365854
2007	35.70175438596491
2008	33.996539792387544