Colorado constitution
Article XXIX
Section 3

(6) The fifty-dollar ($50) limit set forth in subsection (2) of this section shall be adjusted by an amount based upon the percentage change over a four-year period in the United States bureau of labor statistics consumer price index for Denver- Boulder-Greeley, all items, all consumers, or its successor index, rounded to the nearest lowest dollar. The first adjustment shall be done in the first quarter of 2011 and then every four years thereafter.