Year	% of total
1990	6.435092685092686
1991	6.189614137666086
1992	6.148404826656305
1993	6.381724710485463
1994	6.3402187969662025
1995	5.891719106142278
1996	5.890223406435745
1997	6.12316810782284
1998	7.081416679646263
1999	6.721090355657817
2000	6.764329592729843
2001	7.158090649998009
2002	7.316449133247673
2003	7.426108374384236
2004	7.8811709712133435
2005	7.866417711034803
2006	8.599603161815143
2007	8.671700392630626
2008	7.2676930096627945