Year	mm Hg
1980	127
1981	126.8
1982	126.7
1983	126.5
1984	126.4
1985	126.2
1986	126.1
1987	125.9
1988	125.7
1989	125.6
1990	125.4
1991	125.2
1992	125
1993	124.8
1994	124.5
1995	124.3
1996	124.1
1997	123.9
1998	123.8
1999	123.7
2000	123.7
2001	123.7
2002	123.7
2003	123.8
2004	123.8
2005	123.9
2006	124.1
2007	124.2
2008	124.3