An oil drilling rig outside Watford, North Dakota, October 20, 2012. Thousands of people have flooded into North Dakota to work in state's oil drilling boom. REUTERS/Jim Urquhart

No offense to North Dakotans, but their state doesn’t exactly rush to mind when one thinks of the “happiest states” in America. According to the Gallop-Healthway Well-Being Index, however, the Peace Garden State deserves some recognition.

North Dakota made the jump from No. 19 in 2012 to the No. 1 spot in 2013. It unseated the far more predictable happy state of 2012, Hawaii.

The Gallop-Healthways Well-Being Index is based on a set of metrics that take into consideration residents’ personal relationships, economic stability, community, life outlook and physical health. Gallop polled more than 178,000 people across the U.S. for their data.

With all due praise for North Dakota state, the Gallop index shows that happiness may be a Midwest thing. Three of the top ten happiest states in the country border North Dakota: South Dakota, Nebraska and Minnesota. Three others in the top ten: Iowa, Nebraska and Colorado, are nearby as well.

North Dakota ranked first in two of Gallop’s sub-indexes: work environment and physical health.

Dakota’s recent oil boom has provided residents with well-paying jobs. The state has created 56,600 private-sector jobs since 2011, and it has the lowest unemployment rate in the country (3.1 percent).

On the other end of the spectrum, West Virginia is again the lowest-scoring state in the index. West Virginia scored lowest in five of the six sub-indexes, and only Mississippi scored lower in the work environment metric.

Other notable figures from the Gallup index:

Massachusetts scored the highest in basic access, which measures “feeling safe, satisfied, and optimistic within a community.” Alaska scored highest in emotional health, which measures “daily feelings and mental state.” Vermont scored highest in healthy behaviors, which measures “engaging in behaviors that affect physical health.”

All in all, the Gallop-Healthway index shows the U.S. is continuing its steady road of recovery from the 2008 recession: "Well-being has been fairly stable nationally since 2008. However, since 2010, the first full year after the Great Recession officially ended, 11 states' well-being scores have shown year-over-year improvement."