FILE PHOTO: Steam is seen drifting from a factory over the Hoan Bridge in Milwaukee, Wisconsin, in this February, 6, 2014 file photo. REUTERS/Darren Hauck/Files

(Reuters) - A gauge of factory activity in the U.S. Upper Midwest improved to the strongest level in over three years in December, led by much stronger readings on new orders and production, according a private survey released on Friday.

Marquette University and the Institute for Supply Management-Milwaukee said their seasonally adjusted index on manufacturing in the Milwaukee region rose to 65.57 this month from 59.62 in November.

The December figure was the highest since November 2014 when it was 68.9.

A reading above 50 indicates regional factory activity is expanding.

The upbeat snapshot of upper Midwest business activity coincided with a jump in a similar measure for the Chicago area.

On Thursday, MNI Indicators and ISM-Chicago said their jointly developed Chicago Purchase Management Index rose to 67.6 in December, the highest since March 2011.

The Marquette University and Milwaukee ISM survey’s component on new orders, a proxy on future activity, increased to 88.33 from 66.46 last month, while its production gauge improved to 72.65 from 57.94.

Not all the components improved in December. The survey’s employment index fell to 58.67 from 61.73, while its six-month outlook gauge slipped to 71.43 from 73.33.