Year	% of total
1990	90.92913038686213
1991	93.27191036796906
1992	94.68553085245512
1993	96.48836029536103
1994	98.28642091626428
1995	98.45531197301854
1996	98.42650378435799
1997	97.91503034630489
1998	98.10705866037998
1999	97.65778312337787
2000	98.44177721625606
2001	98.77624808788764
2002	99.09815710364657
2003	98.95208674056575
2004	99.07828512521981
2005	99.28028086600351
2006	98.61824623560673
2007	97.82782668343431
2008	97.85099399269214
2009	98.6535955823044
2010	99.78703985397019
2011	99.76598103214681
2012	99.56403911865206
2013	99.74291557113642
2014	99.02865468674113
2015	98.4733714019345