New opiate and crack-cocaine users: characteristics and trends 43 
 
 
Number of 
(crime 
involved) 
OCUs 
170,000 160,000 150,000 140,000 130,000 120,000 110,000 100,000 
Implied 
arrest rate 
(based on 
DIP 2008 
figures) 
15% 16% 17% 18% 20% 21% 23% 25% 
Probability 
of first 
arrest in 
2013 
4.1% 4.0% 3.8% 3.7% 3.4% 3.2% 2.8% 2.4% 
Estimated 
capture of 
original 
cohort in 
2013 
6,955 6,366 5,752 5,113 4,455 3,782 3,102 2,429