Computer programmers
The IT occupation expected to show the weakest growth is computer programming, which is also the profession most susceptible to offshoring.
The number of people employed as computer programmers will increase by just 12% through the decade, from 363,100 in 2010 to 406,800 by 2020, the BLS projects.
That's less than the expected 14% increase in the number of U.S. jobs across all occupations, IT and otherwise, over the same period, according to the BLS.
Offshoring was blamed for relatively weak growth in demand for computer programmers.
"Since computer programming can be done from anywhere in the world, companies often hire programmers in countries where wages are lower," said the BLS. "This ongoing trend will limit growth for computer programmers in the United States."
The median pay for programmers in 2010 was $71,380.
Help desk, technical support
The healthcare industry's growth and its shift to electronic records will help spur demand for computer support specialists, a job category that includes help desk personnel.
There were 607,000 people employed in computer support in 2010. That figure is expected to grow to 717,000 by 2020, for an 18% increase.
The 2010 median pay for computer support specialists was $46,260.
Technical support workers are also being hurt by a shift of jobs to other countries, though the BLS is a little more optimistic about the outlook for this occupation.
"A recent trend to move jobs to lower-cost regions of the United States may offset some loss of jobs to other countries," the bureau said, referring to the trend of hiring people who handle call center duties largely from their homes.
Systems analysts
The BLS projects that the number of computer systems analysts will grow by 22% through 2020, thanks to the spread of mobile networks and the expanded use of computerized healthcare tools, such as e-prescription systems.
The number of computer system analysts in the U.S. in 2010 was 544,000. That figure is expected to rise 22% to 664,800 by 2020. The median salary of a systems analyst was $77,740 in 2010.
Software developers
The BLS said there were 913,100 software developers in the U.S. 2010; they were earning a median salary of $90,530.
The bureau forecasts that the number of software development jobs will increase by 30%, or 270,900, through 2020.
The fastest rate of growth (32%) will be for system software developers, and the lowest (28%) will be for application developers, the bureau said.
Other IT occupations
In 2010, there were 347,200 network and computer systems administrators employed in the U.S., earning a median wage of $69,160. Employment in these occupations is expected to grow by 96,600 jobs, or 28%, through 2020.
The BLS lumps information security analysts, Web developers and computer network architects in a single category. It said a combined 302,300 people held those positions in 2010 and projected that employment in that category would grow 22% to 367,900 jobs by 2020. The median pay for all workers in that category was $75,660 in 2010.