Blue Cross and Blue Shield of Illinois, the state's largest insurer, has announced its business may not grow for the first time in 25 years. The top executive at the insurer said the recession and rising number of unemployed consumers will lead to losses in the number of health plan subscribers. Illinois Blue Cross, which grew its enrollment 2%, to 7.3 million plan members, last year from 2007, did not say how much it expected its membership to decline.