Question: From 1961 to 1980, what was the highest percentage of land used for agriculture in the Republic of Benin?
SQL: SELECT MAX(T1.Value) FROM Indicators AS T1 INNER JOIN Country AS T2 ON T1.CountryCode = T2.CountryCode WHERE T1.Year >= 1961 AND T1.Year < 1981 AND T1.IndicatorName LIKE 'Agricultural land (% of land area)' AND T2.LongName = 'Republic of Benin'