Year	% of total
1990	13.526610953119684
1991	13.656264340583192
1992	14.058333628683776
1993	14.248300725173378
1994	9.014846892348075
1995	9.090896192819262
1996	9.165468485624825
1997	9.161671515365565
1998	8.963911025502098
1999	8.861643452119528
2000	8.804233225286653
2001	8.90306381770734
2002	8.666317511941358
2003	8.88405377398097
2004	8.838595536427073
2005	8.625414119333685
2006	8.72613493237104
2007	8.808884727049564
2008	8.912096687855481