CREATE TABLE table_204_535 (id DECIMAL, "pos" TEXT, "rider" TEXT, "manufacturer" TEXT, "laps" DECIMAL, "time/retired" TEXT, "grid" DECIMAL, "points" DECIMAL)

how many riders had no points ?
SELECT COUNT("rider") FROM table_204_535 WHERE "points" IS NULL
SELECT COUNT("rider") FROM "table_204_535" WHERE "points" IS NULL