The amount of a residential ground rent may be changed on demand of either the obligor or obligee at the end of five years from the date of the agreement, and every five years thereafter, by giving notice in writing by registered mail to the other party between the ninetieth and sixtieth day prior to such fifth anniversary. Unless the parties agree otherwise, such change in ground rent shall not exceed the percentage change for the preceding three years in the General Consumer Price Index for All Items as published by the United States Department of Labor, Bureau of Labor Statistics or such other instrument or agency of the United States or of this Commonwealth as may be designated by the General Assembly. The first of such years shall constitute the base year.
1975, c. 363.