user: Question: What is the total Tonnage GRT with a Type of Cargo ship, and a Nationality of Norway?
Columns: ['Date', 'Ship', 'Type', 'Nationality', 'Tonnage GRT']
Types: ['text', 'text', 'text', 'text', 'real']
Sample row: ['2 Dec 16', 'Voltaire', 'Cargo ship', 'United Kingdom', 8618.0]
SQL:

assistant: SELECT SUM("Tonnage GRT") FROM "Table" WHERE "Type" = 'Cargo ship' AND "Nationality" = 'Norway';