List the date of perpetrators in descending order of the number of people killed.
SELECT Date FROM perpetrator ORDER BY Killed DESC
SELECT Date FROM perpetrator ORDER BY Killed DESC
[{'Date': '04.26 April 26/27'}, {'Date': '11.18 Nov. 18'}, {'Date': '05.21 May 21'}, {'Date': '09.20 Sep. 20'}, {'Date': '04.00 April'}]