user: Question: How many entries for 100 occur when the average is 15.78?
Columns: ['Year', 'Matches', 'Innings', 'Not out', 'Runs', 'High Score', '100', '50', 'Average', 'Strike rate', 'Catches/Stumpings']
Types: ['real', 'real', 'real', 'real', 'real', 'text', 'real', 'real', 'text', 'text', 'text']
Sample row: [2005.0, 14.0, 14.0, 0.0, 221.0, '39', 0.0, 0.0, '15.78', '66.76', '4/–']
SQL:

assistant: SELECT COUNT("100") FROM "Table" WHERE "Average" = '15.78';