The jobless rate reached 13 percent in September, up from 12.8 percent in August, according to a report issued Friday by the state Department of Labor and Training. The latest stop on a seemingly inexorable climb that started three years ago set yet another record since the federal government began tracking the number of unemployed workers in 1976.

Economists who once projected that the rate would hit its apex this year now believe it will continue to rise through the end of 2010.

“In the spring, our forecast was very optimistic,” said Edinaldo Tebaldi, assistant professor of economics at Bryant University. “It turned out to be wrong.”