Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Built | Ship | Operator | Tonnage | Flag |
| --- | --- | --- | --- | --- |
| 2006.0 | Costa Concordia | Costa Cruises | GT | Italy |
| 2007.0 | Costa Serena | Costa Cruises | GT | Italy |
| 2008.0 | Carnival Splendor | Carnival Cruise Lines | GT | Panama |
| 2009.0 | Costa Pacifica | Costa Cruises | GT | Italy |
| 2011.0 | Costa Favolosa | Costa Cruises | GT | Italy |
| 2012.0 | Costa Fascinosa | Costa Cruises | GT | Italy |
Question:
What tonnage was built in 2007?
Answer:
GT