Stena Line has reported its highest number of North Sea passengers for three years in its figures for 2010. For the first time since changing its Harwich to Hook of Holland operations to a twice-daily service in 2007, the ferry giant carried over half a million passengers in a year. Stena Line is attributing part of the 8.7% annual growth in North Sea passengers to reinvigorated interest in ferry travel, fuelled both by the two new-build Superferry vessels it launched on the route in May and October and by difficulties affecting the UK aviation industry. Growth during the final quarter of the year, which saw the launch of the second of the two new Superferries, was particularly strong, with 10,000 more passengers travelling than during the same period in 2009 (a 10.3% increase).