Write SQL query to solve given problem: Calculate the average percentage of word appearance in the page that have revision page id smaller than 106680.. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT CAST(SUM(T1.words) AS REAL) * 100 / SUM(T2.occurrences) FROM pages AS T1 INNER JOIN pages_words AS T2 ON T1.pid = T2.pid WHERE T1.revision < 106680