Year	Percent change (Units)
1980	-19.050
1981	16.795
1982	2.045
1983	-35.747
1984	17.448
1985	46.196
1986	-7.475
1987	-10.786
1988	-16.257
1989	61.113
1990	15.938
1991	62.085
1992	-5.655
1993	0.481
1994	26.493
1995	58.498
1996	-7.799
1997	23.488
1998	-24.672
1999	-1.006
2000	43.441
2001	-8.624
2002	11.071
2003	52.453
2004	-12.612
2005	7.077
2006	20.559
2007	45.765
2008	6.939
2009	3.301
2010	-3.152
2011	-16.482
2012	19.612
2013	32.190
2014	20.564
2015	-4.555
2016	23.915
2017	5.025
2018	0.762
2019	-13.611
2020	5.660
2021	-1.944
2022	-14.231
2023	17.322
2024	14.508
2025	9.779
2026	8.951
2027	8.931
2028	7.677
2029	7.825