The number of crimes reported in Japan in 2015 hit a postwar low, the National Police Agency said Thursday, attributing the trend to an increase in security cameras as well as raised public awareness of crime prevention.

Overall penal code violations decreased 9.3 percent from the previous year to 1,099,048, falling below the previous record of 1,190,549 set in 1973, the agency said in a preliminary report.

All crime categories marked declines from 2014.

The number of thefts, which account for more than 70 percent of crimes in Japan, dropped to 807,605 from 897,259, while murders fell to 933 from 1,054.

Fraud cases dropped to 39,439 from 41,523, but cases of furikome sagi (bank transfer scams) or phone scams rose 1,474 to 12,729.

The crime clearance rate, or the percentage of cases solved by police to total reported crimes, improved to 32.5 percent from 30.6 percent, with the ratio for murder and other violent crimes rising to 72.3 percent from 68.2, topping the 70 percent mark for the first time in 16 years.

By age, the number of crimes committed by juveniles aged between 14 and 19 fell sharply to 39,501 from 142,594 in 2002, when the total number of penal code violations was at its peak.

Crimes by seniors aged 65 or older, meanwhile, nearly doubled to 47,643 from the 2002 figure of 24,241, reflecting Japan's graying society.