April 25, 2012 -- For the 11th year in a row, Maine is the most peaceful state in America, according to the 2012 United States Peace Index report.
The report, produced by the Institute for Economics and Peace in Washington, D.C., also named Louisiana as the country's least peaceful state. It has held this position for the last 20 years.
To create this annual coast-to-coast ranking, researchers looked at five key measurements.
Each state's peace index score was determined by analyzing its homicide, violent crime, policing, and prison rates, as well as by the availability of guns among its residents.
Maine earned the No. 1 spot by having the lowest levels in the land for violent crime, people in prison, and number of police employees. It was one of four New England states to make the nation's top 10 most peaceful places.
The report defined peace as "the absence of violence."
Wyoming made the biggest strides to becoming a more peaceful state, moving from 23rd place last year to 17th place in 2012. Meanwhile, Arizona slipped into the bottom five because of a rising homicide rate.
There were encouraging signs with 35 out of 50 states improving this year. Forty states had reduced levels of violent crime, 34 states sent fewer people to prison, and 29 had lower homicide rates.
Among regions, the Northeast was considered the most peaceful area with the country's lowest homicide, violent crime, and prison rates. It was followed by the Midwest, West, and lastly, the South, which had the highest rates of gun ownership.
The report shows "that over the past 20 years, America has become substantially more peaceful, witnessing a significant and sustained reduction in direct violence," Institute for Economics and Peace Chairman Steve Killelea says in a news release.
He credits this to lower homicide rates in the U.S., which have been cut in half since 1991, and a nearly 50% drop in rates of violent crime during the same period.