Write SQL query to solve given problem: What is the percentage of the words that have been repeated under 180 times in the Catalan language?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT CAST(COUNT(CASE WHEN T2.occurrences < 180 THEN 1 ELSE NULL END) AS REAL) * 100 / COUNT(T1.lid) FROM langs AS T1 INNER JOIN langs_words AS T2 ON T1.lid = T2.lid WHERE T1.lang = 'ca'