Year	Percent
1990	39.516
1991	39.476
1992	39.462
1993	39.463
1994	39.474
1995	39.524
1996	39.61
1997	39.7
1998	39.807
1999	39.951
2000	40.125
2001	40.264
2002	40.424
2003	40.604
2004	40.772
2005	40.957
2006	41.23
2007	41.515
2008	41.824
2009	42.135
2010	42.453
2011	42.821
2012	43.224
2013	43.646
2014	44.038
2015	44.4
2016	44.721
2017	45.014
2018	45.293
2019	45.548
2020	45.774
2021	45.979
2022	46.152
2023	46.302
2024	46.447
2025	46.596
2026	46.753
2027	46.909
2028	47.064
2029	47.217
2030	47.369