About 80 per cent of corruption cases probed by the Central Bureau of Investigation reached the trial stage and accused persons were convicted in 62 percent cases in the past decade, according to the Central government. In response to a query, the government on Wednesday informed the Lok Sabha that the CBI concluded investigations in 7,217 cases between 2006 and June 30, 2016. In the courts, 4,054 of the 6,533 cases ended in conviction during the same period. In all, 671 cases were closed and recommendations for regular departmental action were made in 641 cases. On the issue of the coal block scam, the government informed the Parliament that 53 cases have been registered for alleged violation of the allocation policy. Investigations are still pending in 33 cases. The CBI has registered 33 cases against 34 companies in connection with a comprehensive preliminary enquiry into allegations of irregularities in allocation of coal blocks to 196 companies in 2006-09. The agency has filed final reports in 16 cases, while the probe is underway in other cases. In the second preliminary enquiry pertaining to allocations between 1993 and 2005, the CBI has registered 14 cases and filed final reports in the court in three cases. The agency has registered three cases related to the third preliminary enquiry into allegations of irregularities in the allocation of 101 coal blocks through the dispensation route.