For FECA employees:
(08/19/14) The percentage increase in the December CPI-W index from year to year determines the FECA COLA increase. The 2014 FECA COLA will be 1.5% effective March 2014. After the seventh month of the twelve-month adjustment period for the 2015 FECA COLA, the CPI-W index has risen 2.335%.

via APWU | American Postal Workers Union, AFL-CIO.