According to the Illinois Secretary of State 2012 DUI FactBook, 85% of all people arrested for DUI in Illinois in 2010 were first-time offenders. Also according to the report, 3,440 motorists resulted in revocations after their second offense, 866 for their third, and 436 for their fourth or later (a revocation only occurs after a conviction, and does so automatically). The overall number of DUI arrests has decreased annually from 2008 through 2010 as well.
Unless police simply aren't arresting as many people for some reason, it would appear that Illinois' efforts at preventing recidivism, or the tendency to re-offend, are largely effective.
In Illinois, motorists charged with DUI for the first time are generally eligible for a special one-time chance to dispose of their case via a sentence of Court Supervision. After a finding of guilty, whether after trial or plea of guilty, a defendant can avoid a conviction and jail as long as they comply with certain conditions. This is no free ride - there are significant fines, alcohol education classes and treatment are required, and a criminal record remains forever. The Court also requires a VIP or victim impact panel run by MADD, and can require significant community service, random alcohol testing and other conditions.
Consistent with the Secretary of State's previous reports on the issues I've written about, the cost of a DUI remains extremely high, and the Secretary of State still pegs the estimated cost of a first DUI at over $16,000.