Write SQL query to solve given problem: Among the recipes from The California Tree Fruit Agreement, calculate the percentage of sodium-free recipes.. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT CAST(SUM(CASE WHEN T2.sodium < 5 THEN 1 ELSE 0 END) AS REAL) * 100 / COUNT(*) FROM Recipe AS T1 INNER JOIN Nutrition AS T2 ON T1.recipe_id = T2.recipe_id WHERE T1.source = 'The California Tree Fruit Agreement'