Year	Percent change (Units)
1980	13.300
1981	14.660
1982	13.243
1983	14.558
1984	2.604
1985	10.457
1986	2.411
1987	-6.986
1988	-3.934
1989	0.645
1990	-0.203
1991	-2.848
1992	-0.757
1993	-2.909
1994	24.550
1995	19.200
1996	3.842
1997	1.623
1998	-2.024
1999	-1.554
2000	3.365
2001	4.083
2002	2.266
2003	4.386
2004	-2.593
2005	2.879
2006	6.888
2007	0.867
2008	9.250
2009	3.581
2010	1.486
2011	1.194
2012	5.889
2013	3.971
2014	17.775
2015	1.403
2016	4.946
2017	4.180
2018	1.612
2019	2.752
2020	0.881
2021	4.259
2022	5.579
2023	3.166
2024	4.705
2025	4.563
2026	3.818
2027	3.228
2028	3.000
2029	3.000