Year	Percent
1990	64.018
1991	65.061
1992	66.204
1993	67.464
1994	68.022
1995	68.394
1996	68.462
1997	68.565
1998	68.637
1999	68.488
2000	68.31
2001	68.134
2002	67.949
2003	67.693
2004	67.421
2005	67.416
2006	67.328
2007	67.521
2008	68.072
2009	69.222
2010	68.747
2011	68.554
2012	68.307
2013	68.041
2014	67.828
2015	67.57
2016	67.402
2017	67.344
2018	67.275
2019	67.14
2020	66.907
2021	66.592
2022	66.202
2023	65.734
2024	65.184
2025	64.548
2026	63.835
2027	63.043
2028	62.197
2029	61.341
2030	60.506