The Internal Revenue Service is subjecting a relatively small percentage of wealthy taxpayers to tax audits, and less than half of the biggest corporations in the U.S. are now being audited, according to a new report.

The report, from Syracuse University’s Transactional Records Access Records Clearinghouse, or TRAC, found that 97 out of every 100 individual taxpayers who reported over $1 million in income weren’t audited last year, based on IRS statistics. In fiscal year 2010, such audits turned up $5.1 billion in unreported taxes. Now with just half the audits, the government uncovered only $1.9 billion in unreported taxes in fiscal 2018.

The Internal Revenue Service has been dealing with a series of budget cuts over the past decade, and it has been forced to reduce the number of audits it conducts as other priorities, such as implementing new tax laws, curbing identity theft and updating aging computer systems have taken a greater priority.

TRAC’s research also found that more than half of the 633 largest corporations in the country, those with over $20 billion in assets, weren’t audited last year. This is the first year the audit rate has slipped below 50 percent, TRAC noted. As recently as 2010, 96 percent of such returns were being examined by IRS. Audits in 2010 of large corporations (those with greater than $250 million in assets) uncovered $23.7 billion in unreported taxes. That number was halved to only $12.5 billion during fiscal year 2018.

At the same time, criminal prosecutions have also plunged dramatically. IRS referrals of taxpayers for criminal prosecution relative to population size plummeted 75 percent in the past 25 years, dropping 63 percent in only the past five years. The number of taxpayers convicted after IRS investigations slid to an all-time low in fiscal 2018. There were only 530 convictions for tax fraud.

The report noted that for years, Congress has slashed the budget at the IRS, forcing it to cut back on staff dedicated to audits and criminal investigation. In 2010 IRS had more than 100,000 employees on staff. By June 2018, staffing had dropped 22 percent to just 79,071. Revenue agents and criminal investigators have fallen even more. Despite the additional responsibilities IRS was assigned to implement the Tax Cuts and Jobs Act of 2017, the IRS had 3,000 fewer employees than it had before the tax overhaul was passed.