U.S. Census figures for the region keep teasing us. Every time a new report on population trends comes out, it contains a large measure of disappointment and a dash of optimism.

That's the case with the 2010 Census, which extended the region's losing record to a sixth straight decade.

The seven-county metro area lost 74,802 people, leaving 2,356,285 residents in Allegheny, Armstrong, Beaver, Butler, Fayette, Washington and Westmoreland counties. Only Butler and Washington saw increases. Allegheny lost the most people (58,318) and Fayette said goodbye to the largest proportion of population (8.1 percent). The city of Pittsburgh suffered a bigger loss of share, 8.6 percent or 28,865 residents.

So where was the good news? It came in estimates by the Census Bureau that suggested things started turning around in the final year of the decade. They showed that, from mid-2009 to mid-2010, there was a net gain for the region. Christopher Briem, a regional economist at the University of Pittsburgh who studies population trends, called it "the first overall increase in the regional population in decades."

Let's hope it holds, but it's too soon to celebrate. To understand why, look back a decade, to the release of the 2000 Census data. The figures showed a 1.5 percent drop for the six-county metro region that was used in the statistical models at that time. (Armstrong was added in 2003.) That rate of decline was significantly less than any since the 1950s, and it was seen as a sign that the people drain had bottomed out.

It hadn't. Unfortunately, in the next decade the region went on to lose another 3.1 percent of its residents. And although Pittsburgh's loss rate improved, from 9.5 percent between 1990 and 2000, an 8.6 percent drop in the last 10 years was significant nonetheless.

But Mr. Briem believes a look at snapshots from 2000 and 2010 don't give a full picture of what has been happening in the region. The early part of the decade was the tail end of the decline that was precipitated by the loss of the steel industry in the 1980s, but trends for the second half of the decade are different.

The computer models that Mr. Briem studies at Pitt's University Center for Social and Urban Research indicate the population soon will start showing small or moderate growth. We can only hope that data isn't just teasing us, too.