Flashback four years to a time when nearly 3.55 million Americans called themselves IT professionals. As the economy soured over the next few years, 70,000 people left the IT workforce. Now, after a slow recovery, the number of people saying they're IT pros is back to where it was four summers ago.

An InformationWeek analysis of Bureau of Labor Statistics data shows that it's not just the number of people in the IT workforce that has rebounded. The number of IT pros actually employed reached nearly 3.43 million in the second quarter, up 128,000, or 3.9%, from a year earlier. That's the highest the number of employed IT pros there has been since 2001, when nearly 3.46 million held IT jobs.

There also has been a realignment in the IT workforce over the past four years as many of those who quit the profession in the wake of the dot-com bust came back to it, but often in more traditional roles. Corporate America, in this Internet-tied world, needs these people's skills to run IT systems that drive productivity, says economist Tracy Clark, associate director of Arizona State University's Bank One Economic Outlook Center. "Employers hire people where they can see it makes a difference in productivity," Clark says. "And that's where the IT part comes in."

The four-year realignment has meant a loss of 180,000 programmers, a nearly 25% decline to 558,000 as companies use more prepackaged apps and send more programming assignments offshore. Also in the last four years, the number of computer scientists and analysts has fallen by 38,000 to 777,000, computer-support specialists are off 8,000 to 349,000, and network systems and data communications analysts are down 10,000 to 346,000.

The biggest employment gains came among computer and IS managers, up 70,000 to 340,000. The number of computer software engineers grew 87,000 to 736,000, database administrators are up 27,000 to 195,000, and network and computer-systems administrators jumped 21,000 to 195,000.

The government surveys 60,000 households monthly to determine employment levels. The sample size is big enough to give economists confidence in the overall unemployment rate, which last month stood at 5%. But the data is less reliable as the sample size shrinks for each job category. To compensate for the smaller sample size, InformationWeek aggregates four quarters' worth of data, creating an annualized rate, to determine the latest quarter's employment numbers. The most recent figures reflect a year of quarterly data through June 30.