CALGARY, Alberta - Canadian crude oil exports by rail dropped 36 per cent in July versus the same month a year earlier, according to regulatory data released on Tuesday, adding to a persistent trend of weak rail volumes in Canada.

National Energy Board data showed Canada exported 53,089 barrels per day by rail in July 2016 versus 83,036 bpd in July 2015.

However, July's total was a gain from June's 43,205 bpd, which were the lowest in four years.

Demand to export Canadian crude by rail has dropped sharply since the high point of around 180,000 bpd in 2014, as new and expanded North American crude pipelines have opened up, allowing producers to reach U.S. markets more cheaply.