instruction: Percentage of questions in a given tag per week.
response: SELECT number = ROW_NUMBER() OVER (ORDER BY YEAR(CreationDate), TIME_TO_STR(CreationDate, '%W')), (CAST(SUM(CASE WHEN (Tags LIKE '%<##Tagname##>%') THEN 1 ELSE 0 END) AS FLOAT) * 100 / COUNT(Posts.Id)) AS "perc" FROM Posts WHERE (PostTypeId = 1 AND CreationDate >= '##Date1##' AND CreationDate <= '##Date2##') GROUP BY YEAR(CreationDate), TIME_TO_STR(CreationDate, '%W') ORDER BY YEAR(CreationDate), TIME_TO_STR(CreationDate, '%W')