The following is displayed here:

• The date, on which the currently effective rent is based.
• The percentage points, by which the cost-of-living and operating costs index has changed in the mean time (up to the most recent status before the key date).

In the example, the current rent is based on the status of 04/01/1995, the last status maintained before the key date is from December 1995.

For the cost-of-living and operating costs index, the percentage difference compared with the previous year is maintained in Customizing for each month.
An increase of the index of 0.5% for two months has been maintained and an increase of 1% for 6 months.

In total, this results in a rent increase of

(2 x 0.5% + 6 x 1%) / 12 = 0.583 %