user: Question: What is the total of Matches with Goals of 18, and an Average larger than 0.55?
Columns: ['Goalkeeper', 'Goals', 'Matches', 'Average', 'Team']
Types: ['text', 'real', 'real', 'real', 'text']
Sample row: ['José Bermúdez', 18.0, 33.0, 0.55, 'Cultural Leonesa']
SQL:

assistant: SELECT SUM("Matches") FROM "Table" WHERE "Goals" = 18.0 AND "Average" > 0.55;