SELECT year_film, film, category, num_noms, 100.0 * num_noms / SUM(num_noms) OVER (PARTITION BY year_film, category) as pct_noms
FROM (
SELECT year_film, film, category, COUNT(*) as num_noms
FROM the_oscar_award
WHERE winner = 'False'
GROUP BY year_film, film, category
) as subquery;