Database: codebase_community
Question: Based on posts posted by Community, calculate the percentage of posts that use the R language.
SQL: SELECT CAST(SUM(IIF(T3.TagName = 'r', 1, 0)) AS REAL) * 100 / COUNT(T1.Id) FROM users AS T1 INNER JOIN postHistory AS T2 ON T1.Id = T2.UserId INNER JOIN tags AS T3 ON T3.ExcerptPostId = T2.PostId WHERE T1.DisplayName = 'Community'