Year	Percent change (Units)
1980	-6.664
1981	2.616
1982	-1.264
1983	12.609
1984	24.344
1985	6.489
1986	8.534
1987	5.937
1988	3.932
1989	4.407
1990	3.573
1991	-0.151
1992	7.008
1993	8.649
1994	11.932
1995	8.000
1996	8.698
1997	13.465
1998	11.690
1999	11.595
2000	13.000
2001	-2.462
2002	3.669
2003	5.123
2004	10.984
2005	6.490
2006	6.419
2007	2.566
2008	-2.148
2009	-12.627
2010	12.968
2011	4.816
2012	2.449
2013	1.212
2014	5.160
2015	5.191
2016	1.458
2017	4.710
2018	4.038
2019	1.197
2020	-9.014
2021	14.473
2022	8.584
2023	-1.700
2024	1.106
2025	1.987
2026	2.422
2027	2.476
2028	2.308
2029	2.144