Please list out all annual indicator names of Sudan in 1961?
Sudan is the name of the country; Periodicity = 'Annual'; Year = '1961'
SELECT T1.IndicatorName FROM Indicators AS T1 INNER JOIN Series AS T2 ON T1.IndicatorName = T2.IndicatorName WHERE T1.CountryName = 'Sudan' AND T1.Year = 1961 AND T2.Periodicity = 'Annual'