Year	Percent change (Units)
1980	7.337
1981	12.355
1982	9.638
1983	4.661
1984	3.664
1985	4.133
1986	4.386
1987	4.202
1988	4.087
1989	5.203
1990	4.917
1991	4.111
1992	1.788
1993	1.814
1994	0.039
1995	2.052
1996	2.049
1997	1.004
1998	1.141
1999	2.365
2000	3.128
2001	1.069
2002	3.820
2003	1.708
2004	2.293
2005	2.305
2006	1.389
2007	2.496
2008	1.841
2009	0.787
2010	2.228
2011	2.661
2012	0.993
2013	0.956
2014	1.974
2015	1.273
2016	1.414
2017	1.833
2018	2.054
2019	2.062
2020	0.779
2021	4.734
2022	6.642
2023	3.179
2024	2.051
2025	1.881
2026	1.898
2027	1.850
2028	1.955
2029	2.014