In 2006, the New York City Independent Budget O:ice (IBO) issued a report analyzing how property tax burdens shifted in New York City during the 25 - year period after the enactment of the NY RPTL Chart 4 shows the changes in e:ective tax rates by property type from FY1984 to FY2007. 1-3 Unit Family Co-Ops Condos Walkups Class 3 Class 4 % Change -65% -29% -28% -7% 12% -18% Chart 4. Percentage Change in Net Effective Tax Rates, FY1984-2007