Year	mm Hg
1980	125.2
1981	125.2
1982	125.2
1983	125.3
1984	125.3
1985	125.4
1986	125.4
1987	125.4
1988	125.3
1989	125.3
1990	125.1
1991	125.1
1992	124.9
1993	124.7
1994	124.5
1995	124.4
1996	124.3
1997	124.4
1998	124.4
1999	124.5
2000	124.5
2001	124.6
2002	124.7
2003	124.9
2004	125
2005	125.2
2006	125.4
2007	125.5
2008	125.7