The vast majority of cannabis consumed in Canada is grown in the country - to the point that the report found it was comparable to the domestic production of tobacco, beer and wine combined.

The $5.7 billion spent on cannabis (more than 90% of which was for non-medical purposes) compares to 2016 alcohol purchases of $22.3 billion and tobacco purchases of $16.0 billion, the agency said.

Canada is expected to pass legislation to legalize recreational marijuana effective July 1, but complications in setting up distribution and effective controls could delay the launch.

Most of the cannabis consumed was produced in Canada, with only about Can$300 million worth of illegal pot smuggled into the country.

The data agency estimates Canadian adults spent $5.7 billion on marijuana previous year - 90 per cent of it for illegal, non-medical purposes.

It concluded that almost five million Canadians spent money on marijuana a year ago, spending an average of about $1,200 each for a total of $5.7 billion.

The export figures were key because they help researchers understand the possible impacts of the industry on Canada's gross domestic product, he said.

It also estimated that Canadians imported about 300 million Canadian dollars (roughly 240 billion US dollars) worth of illegal marijuana last year while Canada exported 1.2 billion Canadian dollars worth of illegal cannabis last year, Statistics Canada revealed.

All the estimates are provisional and rely heavily on assumptions, the agency said, and they could be subject to large revisions. The price of marijuana was 7.5 Canadian dollars (six USA dollars) a gram a year ago.

By past year, the price of a gram had fallen to $7.50 a gram, the report estimates.

Spending on pot, the agency said, has increased an average of six percent annually since 1961. In 1975, people in that age group made up four per cent of total household spending and in 2017 the share had grown to 23 per cent. It has also unveiled an online portal called the Cannabis Stats Hub, which enables the public to explore some of the data.