Hello,

I need to plot a graph of CO2 sequestered by carbon sinks (ppmv) over time, but want to show the data in three separate time periods:
1960-1975
1975-1990
1990-2011

I want it on the same graph, but with three different colors and 3 different legend titles. Please help!
The data looks like this:

Year ppmv
1960
1961 1.16
1962 1.48
1963 1.63
1964 1.57
1965 1.58
1966 0.95
1967 1.61
1968 1.58
1969 1.11
1970 1.44
1971 1.85
1972 1.64
1973 0.80
1974 2.06
1975 1.77
1976 1.85
1977 1.38
1978 1.34
1979 1.75
1980 1.14
1981 1.65
1982 1.85
1983 1.39
1984 1.74
1985 1.90
1986 1.94
1987 1.72
1988 1.38
1989 2.11
1990 2.33
1991 2.43
1992 2.64
1993 2.86
1994 2.13
1995 1.81
1996 2.06
1997 2.64
1998 1.07
1999 1.95
2000 2.53
2001 2.42
2002 1.78
2003 1.82
2004 2.58
2005 2.31
2006 2.63
2007 2.80
2008 2.74
2009 3.13
2010 2.79
2011 3.30

Any direction would be appreciated!