Year	Percent change (Units)
1980	12.199
1981	5.200
1982	2.400
1983	-22.600
1984	16.900
1985	-14.100
1986	36.300
1987	15.000
1988	11.900
1989	-14.200
1990	43.100
1991	4.200
1992	-7.124
1993	6.704
1994	5.918
1995	23.231
1996	-18.206
1997	-14.338
1998	-13.965
1999	-28.615
2000	-13.822
2001	-18.540
2002	-23.381
2003	8.210
2004	16.296
2005	3.555
2006	13.711
2007	21.163
2008	29.430
2009	-21.059
2010	41.268
2011	15.347
2012	-10.436
2013	6.849
2014	-1.358
2015	-15.639
2016	-6.782
2017	13.887
2018	6.678
2019	-8.759
2020	-21.543
2021	21.187
2022	5.343
2023	9.666
2024	2.453
2025	2.023
2026	2.438
2027	2.332
2028	2.412
2029	2.668