Database: cookbook
Question: Among the recipes from The California Tree Fruit Agreement, calculate the percentage of sodium-free recipes.
SQL: 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'