The Office of the Children's Commissioner (OCC) estimates that between August 2010 and October 2011, around 2,409 children were identified as having been sexually exploited, with a further 16,500 being identified as at risk. However, the OCC says that evidence suggests that the number is far greater. It is difficult to know how many children are affected by child sexual exploitation as it is a significantly under-reported crime. Young people often aren't aware they've been exploited.