Year	Percent change (Units)
1980	-83.637
1981	107.614
1982	-36.810
1983	57.435
1984	188.394
1985	-62.913
1986	-66.207
1987	416.499
1988	-4.670
1989	-3.826
1990	-38.201
1991	83.486
1992	-20.365
1993	-17.850
1994	25.402
1995	34.800
1996	-39.968
1997	17.827
1998	4.364
1999	32.271
2000	-58.827
2001	13.550
2002	-0.702
2003	-28.272
2004	-24.343
2005	61.648
2006	-38.988
2007	220.773
2008	-25.571
2009	-20.790
2010	-9.444
2011	68.998
2012	-10.728
2013	-18.245
2014	35.541
2015	-7.061
2016	3.372
2017	30.244
2018	-46.912
2019	51.884
2020	-24.978
2021	-9.896
2022	-7.066
2023	3.177
2024	11.133
2025	7.595
2026	8.045
2027	3.056
2028	3.135
2029	4.155