Many criminal justice professionals are convinced that offender pay-backs (fines and fees) can be a revenue source to fill the gap of diminishing citizen revenues. Texas adult probationers, for example, paid $29 million in user fees last year; this was 40 percent of the State's probation department budget. The monetary yield of fine and fee systems, however, varies according to the effectiveness of a jurisdiction's collection and enforcement system. Jurisdictions with collection rates of 80 percent or higher generally restrict the use of installment plans, allow just 2 weeks to 30 days for payment, and strictly enforce penalties for nonpayment. Such systems are typically implemented through computerized monitoring systems. Critics of the fine system allege that it is disproportionately severe for poor offenders and an easy out for wealthy offenders. The "day fine" system used in Europe is being examined by many jurisdictions to counter this criticism. The "day fine" system calculates a fine according to an offender's ability to pay and the severity of the crime.