The Navy will need about $9 billion more in its annual shipbuilding budget to grow the fleet to 350 ships, close to the size needed according to a new force structure assessment released last month and matching President-elect Trump’s vision for the service.

The Navy has spent $15.9 billion in its shipbuilding account each year over the past 30 years on average, according to a report released this week from the Congressional Budget Office. But building and maintaining a fleet of 350 ships, close to the 355 requested by the assessment, would cost $25 billion per year, about 60 percent more than the historical average, the report said.