Reword this paragraph
Opioids, mainly heroin, were cited as the primary drug for entering treatment by around 216 000 or 51% of all those reported entering specialist drug treatment in 29 European countries in 2009.
Approximately 216 000, i.e. 51% of all reported clients entering specialised drugs treatment in 29 European countries in 2009, mention opioids, particularly heroin, as a prime drugs treatment at treatment enrolment.