The most recent indexation was on April 1, 2017, and that was 0.4%. The salaries would have increased by 0.4%.
I do have the numbers for recent years. For example, in 2016 it was 1.8%. Going back, it was 2.6%, 1.8%, 2.5%, 2.5%, and 3.6%. It has ranged in the last several years, from a high of 3.9% to a low of 0.4%, which was the most recent.