Year	Percent change (Units)
1980	12.231
1981	11.046
1982	6.101
1983	4.000
1984	3.966
1985	4.624
1986	5.414
1987	5.994
1988	4.051
1989	5.405
1990	4.628
1991	7.304
1992	5.577
1993	2.748
1994	1.367
1995	2.023
1996	1.262
1997	0.561
1998	1.207
1999	1.119
2000	1.732
2001	2.362
2002	1.498
2003	3.657
2004	1.160
2005	1.819
2006	1.958
2007	2.407
2008	4.434
2009	1.666
2010	1.621
2011	3.064
2012	1.912
2013	0.445
2014	1.183
2015	1.878
2016	-0.330
2017	1.500
2018	2.268
2019	2.491
2020	0.039
2021	2.905
2022	5.605
2023	3.059
2024	2.042
2025	2.244
2026	2.008
2027	1.893
2028	1.899
2029	1.992