Year	mm Hg
1980	123.5
1981	123.6
1982	123.7
1983	123.7
1984	123.8
1985	123.8
1986	123.8
1987	123.8
1988	123.8
1989	123.8
1990	123.9
1991	123.9
1992	123.9
1993	123.9
1994	123.8
1995	123.8
1996	123.8
1997	123.8
1998	123.9
1999	124
2000	124.1
2001	124.2
2002	124.3
2003	124.5
2004	124.6
2005	124.8
2006	124.9
2007	125.2
2008	125.3