Over 39% of South Koreans say they believe reunification with North Korea is impossible, the highest number since Seoul National University’s Institute for Peace and Unification Studies began its annual poll in 2007.

The results of the institute’s poll released Monday showed respondents who believe reunification is impossible rose 3.5 percentage points from the previous year. The July 1 to 26 poll interviewed 1,200 adults aged 19 to 74 and had a margin of error of 2.8%.

Of the over 60% of respondents who believed reunification was possible, 27.5% said they expected it would take at least 30 years; 16.1%