The Architectural Billings Index (ABI) was back up in May after its second monthly drop of the year.

According to the American Institute of Architects (AIA), May’s ABI score was 51.9, up from 48.8 in April. The ABI reflects the approximate nine- to 12-month lead time between architecture billings and construction spending.

AIA attributes the increase to a growing demand for new schools, hospitals, cultural facilities and municipal buildings. The new projects inquiry index was 61.5, up from a reading of 60.1 the previous month.

“As has been the case for the past several years, while the design and construction industry has been in a recovery phase, we continue to receive mixed signals on business conditions in the marketplace,” says Dr. Kermit Baker, chief economist at AIA. “Generally, the business climate is favorable, but there are still construction sectors and regions of the country that are struggling, producing the occasional backslide in the midst of what seems to be growing momentum for the entire industry.”

The South had the highest regional ABI average (54.6), followed by the Midwest (52.3), West (49.9) and Northeast (45.2).