Lifted by an improving economy and falling fuel prices, Japanese automakers ended 2014 on a strong note with Toyota Motor Corp. hitting a double-digit increase in December sales and Honda Motor Co. and Nissan Motor Co. each breaking annual sales records, data released Monday by Autodata Corp. showed.

Positive economic indicators combined with the recent drop in gas prices gave a final year-end boost to an industry that saw its fifth year of annual growth in new car sales since the recession in the U.S.

Dealers continued a 10-month streak of annual gains in new car sales in December and contributed to the market growing 5.9 percent to 16.52 million vehicles in 2014. The industry last breached the 16 million mark in 2007.