user: ### NOW ANSWER:
Question: What is the sum of Grid, when Time is "+16.687"?
Columns: ['Rider', 'Bike', 'Laps', 'Time', 'Grid']
Types: ['text', 'text', 'real', 'text', 'real']
Sample row: ['Ruben Xaus', 'Ducati 1098 RS 08', 24.0, '39:19.710', 3.0]
SQL:

assistant: SELECT SUM("Grid") FROM "Table" WHERE "Time" = '+16.687';