Last week, Nonprofit Vote released a 26-page report on voter turnout in the November 2014 election.  Here is a link to the report.  Nonprofit Vote does reports like this after each congressional and presidential election.

Page seven shows the turnout in each state as a ranking.  The states are in order of how high turnout was, and that page shows the rank of each state in November 2014 and also November 2010.

The two states that dropped the most in rankings between 2010 and 2014 were Delaware and California.  Delaware was 12th best in 2010, but 37th in 2014.  California was 20th best in 2010, but 43rd in 2014.