Improved weather conditions following a long winter and improved optimism about the national economy may be the driving forces behind the rise in the

The National Restaurant Association’s Restaurant Performance Index in May reached 101.8, a 14-month high.

The National Restaurant Association said the Restaurant Performance Index was 100.6 in March, up .7% from 99.9 in February.

The food service sector may be on the upswing as the National Restaurant Association’s Restaurant Performance Index rose 0.3% in November to 101.2.