Year	mm Hg
1980	112.6
1981	112.8
1982	113.1
1983	113.3
1984	113.6
1985	113.9
1986	114.1
1987	114.4
1988	114.7
1989	115
1990	115.2
1991	115.5
1992	115.8
1993	116
1994	116.3
1995	116.5
1996	116.8
1997	117
1998	117.2
1999	117.3
2000	117.5
2001	117.6
2002	117.7
2003	117.7
2004	117.8
2005	117.7
2006	117.7
2007	117.6
2008	117.6