Write SQL query to solve given problem: In what percentage of counties has the ABC Read project been launched?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT CAST(SUM(CASE WHEN T2.title LIKE 'ABC Read' THEN 1 ELSE 0 END) AS REAL) * 100 / COUNT(T1.school_county) FROM projects AS T1 INNER JOIN essays AS T2 ON T1.projectid = T2.projectid