The U.S. business and residential wireless market will reach $248.5 billion by 2012, growing 12.6% annually from $137 billion in 2007, a new report by Insight Research states.

Though the numbers sound impressive, they’re a decreasing rate, said analyst Linda Kastner who worked on the report Telecom Services in Vertical Markets 2007-2012 for the Boonton, N.J., company.

New subscriptions are coming from landline replacements and from wireless customers converting to data services, she said.

On the business side, “The wireless portion is going to grow at 13.3%, and that would start at $48 billion in 2007, and at $ 89.5 billion in 2012, in 14 verticals,” Kastner said. The top vertical markets are construction; financial, insurance, and real estate; professional services; and transportation. Health care is poised to be another major vertical market for wireless because it’s due for new applications, she said.

Of 26,500 companies surveyed with at least 1,000 employees, AT&T/Cingular leads in market share with 26%, followed by Verizon (25%), Sprint Nextel (23%), and Alltel (6%).