Analysis of information sources in references of the Wikipedia article "Feiertag (Deutschland)" in German language version.
(„Mar 21“ entspricht dabei -W12-7 und „Apr 7“ ist -W14-7, andere Daten entsprechend.)With the ISO leap rule the Gregorian Easter computus yields that following date frequencies:
Mar 21=12.1%, Mar 28=23.5%, Apr 7=23.2%, Apr 14=23.3%, Apr 21=17.6%, Apr 28=0.3%.