Year	Percent change (Units)
1980	5.110
1981	1.631
1982	-1.340
1983	0.605
1984	3.067
1985	3.713
1986	1.836
1987	1.542
1988	3.283
1989	4.431
1990	3.713
1991	-0.929
1992	-0.145
1993	-0.144
1994	1.301
1995	0.563
1996	0.449
1997	2.242
1998	2.936
1999	1.633
2000	4.111
2001	1.620
2002	-0.065
2003	-0.076
2004	2.534
2005	2.849
2006	4.163
2007	3.913
2008	2.695
2009	-2.305
2010	3.206
2011	1.905
2012	1.200
2013	1.836
2014	2.319
2015	1.582
2016	2.085
2017	1.436
2018	2.852
2019	1.157
2020	-2.272
2021	5.397
2022	2.666
2023	0.764
2024	1.341
2025	1.391
2026	1.800
2027	1.200
2028	1.800
2029	1.200