The arrest rate fell below 20 percent in 2001 for the first time since the end of World War II, according to the National Police Agency's annual white paper.
The drop in the arrest rate, which hovered between 34 percent and 45 percent in the 1990s, follows an increase in the number of reported Penal Code violations in recent years, the report says.
The paper, released Friday titled "Toward recovery of our country's public safety," says the number of criminal cases has increased by about 1 million over the last 10 years, reaching around 2.73 million last year.
Nearly 90 percent of the reported crimes involved theft, an increase of about 800,000 over the last 10 years.
The report says community cooperation is indispensable in improving public safety.
Touching on international terrorism, the paper refers to North Korea's admission Sept. 17 that it abducted Japanese citizens during the Cold War.
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