According to the latest Eurobarometer survey on Youth attitude on drugs, about one third of young men aged 15-24 in Slovakia have tried marijuana one time or another.
The survey cites 32% of young men and 20% of young women as having experimented with or used marijuana in the past, with as much as 45% saying they could get hold of it with no problem, which is not far behind the Czech Republic with 51%, but the use of marijuana is decriminalised there.
A summary report of the Eurobarometer study can be viewed here