Year	Percent change (Units)
1980	5.447
1981	6.324
1982	5.256
1983	3.284
1984	2.396
1985	2.084
1986	-0.125
1987	0.242
1988	1.274
1989	2.778
1990	2.687
1991	3.474
1992	5.046
1993	4.476
1994	2.717
1995	1.733
1996	1.274
1997	1.507
1998	0.596
1999	0.647
2000	1.413
2001	1.900
2002	1.326
2003	1.074
2004	1.780
2005	1.928
2006	1.775
2007	2.271
2008	2.754
2009	0.246
2010	1.119
2011	2.482
2012	2.159
2013	1.607
2014	0.769
2015	0.680
2016	0.367
2017	1.702
2018	1.935
2019	1.354
2020	0.371
2021	3.212
2022	8.666
2023	6.030
2024	2.406
2025	2.019
2026	1.971
2027	1.974
2028	1.988
2029	2.009