Figures show that in the 1990-91 school year, 16.6 percent of young people aged 20-24, or almost 340,000 people didn't have a high school diploma and weren't attending school.
Within the same demographic, that number fell to 8.5 percent, or 191,000 people in the 2009-10 school year, StatsCan said.
By gender, the dropout rate was about halved for females and males, although females have a current dropout rate of 6.6 percent compared with 10.3 percent for males, the report said.
The report also highlighted the plight of dropouts in bad economic times.
"During the deepest part of the recent economic downturn in 2008-09, almost one in four dropouts aged 20 to 24 was unable to find work," the agency said. "In addition, the gap between their unemployment rate and that of their counterparts who had completed high school widened."