Year	Percent
1990	29.733
1991	30.062
1992	30.934
1993	31.241
1994	31.472
1995	30.84
1996	31.318
1997	31.863
1998	32.285
1999	33.514
2000	34.778
2001	33.564
2002	36.938
2003	36.632
2004	35.807
2005	38.637
2006	40.897
2007	44.288
2008	46.624
2009	48.737
2010	50.535
2011	53.992
2012	58.248
2013	61.236
2014	63.516
2015	65.863
2016	67.117
2017	67.463
2018	67.786
2019	68.063
2020	68.281
2021	68.439
2022	68.542
2023	68.608
2024	68.669
2025	68.741
2026	68.818
2027	68.906
2028	69.007
2029	69.121
2030	69.249