Year	mm Hg
1980	117.1
1981	117.3
1982	117.5
1983	117.6
1984	117.8
1985	118
1986	118.2
1987	118.4
1988	118.6
1989	118.8
1990	119
1991	119.2
1992	119.5
1993	119.7
1994	120
1995	120.2
1996	120.4
1997	120.7
1998	120.9
1999	121.1
2000	121.2
2001	121.4
2002	121.5
2003	121.6
2004	121.7
2005	121.8
2006	121.9
2007	121.9
2008	121.9