PORTLAND (AP) — An environmental group says a new study shows that extreme rainstorms and snowstorms are happening 74 percent more often in Maine since 1948.

The advocacy group Environment Maine says its report is based on an analysis of state data from the National Climatic Data Center. It says that heavy downpours or snowstorms that used to happen once every 12 months on average in Maine now happen every 6.9 months.

It also shows that the biggest storms are getting bigger. The largest annual storms in Maine now produce 23 percent more precipitation, on average, than they did 65 years ago. An example is the June storm that devastated Brownville and surrounding towns as an example of an extreme rainstorm.