Year	Percent change (Units)
1980	10.359
1981	17.241
1982	-27.359
1983	-32.414
1984	-13.595
1985	-22.497
1986	26.068
1987	-11.068
1988	23.353
1989	-2.520
1990	22.235
1991	32.120
1992	2.784
1993	-1.900
1994	9.192
1995	3.725
1996	-2.071
1997	3.901
1998	1.792
1999	-8.718
2000	4.000
2001	-0.945
2002	-8.489
2003	20.562
2004	9.036
2005	12.618
2006	2.699
2007	3.854
2008	-3.876
2009	-8.519
2010	7.364
2011	9.452
2012	4.228
2013	2.000
2014	2.200
2015	3.970
2016	5.862
2017	-0.308
2018	8.777
2019	-3.377
2020	-14.452
2021	5.674
2022	24.112
2023	-0.984
2024	0.954
2025	10.197
2026	6.393
2027	4.042
2028	4.002
2029	4.057