Year	mm Hg
1980	126.8
1981	126.7
1982	126.6
1983	126.4
1984	126.2
1985	126
1986	125.8
1987	125.6
1988	125.4
1989	125.1
1990	124.9
1991	124.7
1992	124.5
1993	124.3
1994	124.1
1995	123.9
1996	123.8
1997	123.7
1998	123.5
1999	123.4
2000	123.3
2001	123.2
2002	123.1
2003	123
2004	122.9
2005	122.8
2006	122.8
2007	122.7
2008	122.7