Year	mm Hg
1980	124.9
1981	124.7
1982	124.6
1983	124.4
1984	124.2
1985	124.1
1986	124
1987	123.9
1988	123.8
1989	123.6
1990	123.5
1991	123.4
1992	123.2
1993	123.1
1994	122.9
1995	122.7
1996	122.4
1997	122.2
1998	121.9
1999	121.6
2000	121.3
2001	120.9
2002	120.5
2003	120.1
2004	119.7
2005	119.3
2006	118.9
2007	118.5
2008	118.1