percent of voters in midterm compared to previous presidential election

[freepcrusher]

here are the years I have information for:
1930 67.3%
1934 82.5%
1942 56.2%
1946 71.7%
1950 82.9%
1954 69%
1958 73.7%
1962 74.4%
1966 74.9%
1970 74.1%
1974 67.3%
1978 66.9%
1982 73.8%
1986 64.5%
1990 68.1%
1994 67.5%
1998 69.2%
2002 70.9%
2006 66.2%
2010 66%
2014 61%