Year	Percent change (Units)
1980	-13.600
1981	-60.400
1982	-33.000
1983	0.000
1984	7.165
1985	18.862
1986	13.119
1987	10.770
1988	8.219
1989	11.261
1990	7.095
1991	15.444
1992	5.761
1993	18.773
1994	5.129
1995	6.829
1996	15.878
1997	-0.967
1998	21.131
1999	8.171
2000	-0.265
2001	-5.825
2002	-2.044
2003	-0.253
2004	13.760
2005	-0.285
2006	11.567
2007	3.612
2008	8.043
2009	-0.637
2010	12.961
2011	37.586
2012	6.337
2013	8.395
2014	3.656
2015	-8.665
2016	5.004
2017	31.563
2018	1.241
2019	5.121
2020	-6.368
2021	-10.301
2022	4.664
2023	-5.784
2024	6.199
2025	5.497
2026	5.598
2027	4.165
2028	4.997
2029	4.903