Among649,708cases cleared for non-traffic penal code offenses(excluding unsafe driving resulting in death or injury in connection with traffic accidents;hereinafter the same in this subsection)(excluding cases where it was confirmed as a result of investigation that the act in question did not constitute a crime or that the conditions for prosecution or punishment were not satisfied;hereinafter the same in this subsection)in2004,509,985cases(78.5%of the total)were committed by a sole perpetrator and139,723cases(21.5%)were in complicity.508,423cases(78.3%)were committed by adults only(by a sole adult perpetrator or in complicity with adults only),130,779cases(20.1%)by juveniles only(by a sole juvenile perpetrator or in complicity with juveniles only),and10,506cases(1.6%)in complicity with adults and juveniles(Source:Annual Report of Criminal Statistics on Police).
  Fig.4-2-1-18 shows the percent distribution of non-traffic penal code offenses committed by only adults and by only juveniles in2004,by number of perpetrators and type of offense.
  The complicity rate(the rate of cases committed in complicity among total cases;hereinafter the same)was26.8%(down by0.5points from the previous year)for cases by juveniles only and18.5%(up by3.0points(id.))for cases by adults only.

Fig.4-2-1-18  Percent distribution of non-traffic penal code offenses committed by juveniles and by adults,by type of offense and number of perpetrators(2004)

  Fig.4-2-1-19 shows the trend in membership and number of hot rodders since1978.
  With respect to the size of hot rodders,the percentage of those gangs with30or more members fell from9.6%in1995to1.6%in2004,indicating that hot rodders are becoming smaller in scale(Source:The Traffic Bureau,National Police Agency).

Fig.4-2-1-19  Trends in membership and the number of hot rodders(1978-2004)