Year	Percent
1990	40.318
1991	40.494
1992	40.732
1993	40.893
1994	41.115
1995	41.487
1996	41.613
1997	41.952
1998	42.4
1999	42.742
2000	43.029
2001	43.274
2002	43.617
2003	43.84
2004	44.175
2005	46.721
2006	49.303
2007	47.931
2008	46.551
2009	45.175
2010	43.811
2011	42.465
2012	48.785
2013	42.523
2014	42.604
2015	40.96
2016	42.524
2017	42.555
2018	42.59
2019	42.63
2020	42.679
2021	42.739
2022	42.808
2023	42.878
2024	42.938
2025	42.984
2026	43.018
2027	43.039
2028	43.048
2029	43.052
2030	43.055