Database: european_football_1
Question: For all the games ended up with 1-1, what percentage of them are from Liga NOS division?
SQL: SELECT CAST(COUNT(CASE WHEN T2.name = 'Liga NOS' THEN T1.Div ELSE NULL END) AS REAL) * 100 / COUNT(T1.Div) FROM matchs AS T1 INNER JOIN divisions AS T2 ON T1.Div = T2.division WHERE T1.FTHG = 1 AND FTAG = 1