Which is the most violent US state? Which are getting better - and which are getting worse? The US peace index, published by the Institute for Economics and Peace claims to have the answer.

The institute already publishes the respected Global Peace index - which we published the data behind in January.

This is its first attempt to quantify peace in the US, and it has given data over time to try to show how things have changed.

Key findings are:

• The most peaceful state is Maine, followed by New Hampshire. Maine topped the list of states on three of five indicators: number of violent crimes, number of police officers and the incarceration rate

• The least peaceful state is Louisiana, followed by Tennessee

• Southern states were the least peaceful, while states in the northeast were most peaceful

• The cost of violence per person in a state ranges from $656 in Maine to $2,458 in Louisiana

• New York has got a lot more peaceful, experiencing the most significant increase as a result of decreases in violent crime and the murder rate

The index estimates that the economic effect of decreasing violence in states by 25% ranges from $126m in Vermont to $16bn in California.

The institute has given us the historic data for you to play with. What can you do with it?

Data summary

US peace index Click heading to sort. Download this data Rank State 1991 2009 Change, % Rank Change 1 Maine 1.27 1.34 5 1 2 New Hampshire 1.46 1.5 3 2 3 Vermont 1.34 1.54 15 0 4 Minnesota 1.54 1.62 5 3 5 North Dakota 1.16 1.71 48 -4 6 Utah 1.67 1.75 5 3 7 Massachusetts 2.3 1.8 -22 12 8 Rhode Island 2.04 1.83 -10 7 9 Iowa 1.54 1.85 20 -3 10 Washington 2.09 1.87 -11 6 11 Nebraska 1.81 1.88 4 1 12 Hawaii 1.78 1.91 7 -2 13 Oregon 2.19 2.08 -5 4 14 South Dakota 1.47 2.17 47 -9 15 Connecticut 2.45 2.21 -10 6 16 Idaho 1.84 2.24 22 -3 17 Montana 1.62 2.28 40 -9 18 West Virginia 1.79 2.28 28 -7 19 Wisconsin 1.98 2.3 16 -5 20 Kentucky 2.41 2.39 -1 0 21 Pennsylvania 2.19 2.42 10 -3 22 Ohio 2.7 2.43 -10 3 23 Wyoming 2.59 2.49 -4 0 24 Indiana 2.48 2.5 1 -2 25 Virginia 2.75 2.52 -8 2 26 New Jersey 3.12 2.61 -16 5 27 Kansas 2.59 2.63 1 -3 28 Colorado 2.71 2.66 -2 -2 29 New York 3.97 2.69 -32 20 30 Alaska 3.01 2.7 -10 0 31 Michigan 3.48 2.79 -20 8 32 North Carolina 3.27 2.79 -14 2 33 California 3.78 2.89 -24 9 34 Mississippi 2.96 2.97 0 -5 35 Illinois 3.65 2.98 -18 5 36 Delaware 2.91 3.14 8 -8 37 Arizona 3.38 3.14 -7 0 38 New Mexico 3.38 3.16 -7 0 39 Georgia 3.85 3.18 -17 5 40 Missouri 3.29 3.21 -2 -5 41 Maryland 3.95 3.24 -18 7 42 South Carolina 3.92 3.26 -17 3 43 Oklahoma 3.19 3.27 2 -10 44 Arkansas 3.14 3.3 5 -12 45 Texas 3.95 3.3 -16 2 46 Alabama 3.79 3.42 -10 -3 47 Florida 3.92 3.5 -11 -1 48 Nevada 3.7 3.5 -6 -7 49 Tennessee 3.3 3.61 9 -13 50 Louisiana 4.28 3.97 -7 0

• DATA: download the full spreadsheet

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