Year	Percent change (Units)
1980	32.232
1981	31.515
1982	21.753
1983	-5.172
1984	10.583
1985	13.784
1986	-30.309
1987	-31.593
1988	8.112
1989	1.604
1990	14.000
1991	19.812
1992	15.189
1993	10.969
1994	-11.243
1995	4.009
1996	4.772
1997	19.685
1998	19.640
1999	-10.078
2000	5.825
2001	15.296
2002	4.175
2003	9.566
2004	15.737
2005	-5.612
2006	14.238
2007	31.661
2008	21.123
2009	-16.367
2010	-4.014
2011	10.613
2012	22.508
2013	23.926
2014	-4.274
2015	9.985
2016	-12.101
2017	7.158
2018	0.392
2019	-11.823
2020	2.550
2021	-6.316
2022	18.702
2023	4.358
2024	10.797
2025	1.667
2026	1.167
2027	1.755
2028	1.093
2029	3.412