Researchers say they can’t determine why – but new data finds cannabis use in Ontario jumped significantly – in the year before recreational use was legalized.

The survey of 28-hundred Ontario adults by the Centre for Mental Health and Addiction in Toronto finds 19.4 per cent reported using marijuana in 2017 – up from 15.7 per cent in 2016.

The record level followed a steady year-over-year rise in use of the previously illicit drug since 1996.

Senior scientist Robert Mann says the biggest increase over the long term seemed to be among young adults aged 18 to 29 – but the survey also found the percentage of respondents aged 50 and older – who reported previous year use – has also jumped.