Based on business in Phoenix, calculate the percentage of business with low funny votes.
in Chandelier refers to city = 'Chandelier'; percentage = divide(count(business_id where review_votes_funny = 'Low'), count(business_id)); business with low funny votes refers to review_votes_funny = 'Low'
SELECT CAST(SUM(CASE WHEN T2.review_votes_funny = 'Low' THEN 1 ELSE 0 END) AS REAL) * 100 / COUNT(T1.business_id) FROM Business AS T1 INNER JOIN Reviews AS T2 ON T1.business_id = T2.business_id WHERE T1.city = 'Phoenix'