Year	Percent
1990	70.786
1991	71.22
1992	71.18
1993	71.193
1994	71.298
1995	71.302
1996	71.169
1997	70.231
1998	70.047
1999	69.869
2000	69.283
2001	68.907
2002	68.969
2003	68.323
2004	68.254
2005	68.858
2006	68.613
2007	68.406
2008	68.173
2009	68.205
2010	67.951
2011	67.475
2012	67.693
2013	68.148
2014	68.347
2015	68.241
2016	68.633
2017	68.307
2018	67.956
2019	67.587
2020	67.206
2021	66.759
2022	66.298
2023	65.844
2024	65.426
2025	65.062
2026	64.708
2027	64.413
2028	64.158
2029	63.913
2030	63.657