Return every order's id, total and pct_rank: its PERCENT_RANK() by total ascending, rounded to 3 decimals. Sort by total, then id.
PERCENT_RANK is (rank - 1) / (rows - 1), so the smallest order gets 0 and the largest gets 1.
Schema
customers(id, name, country, signup_date)
orders(id, customer_id, order_date, total)