The UK is not the only country where child sex abuse offences are or have been rising rapidly. See New stats on US Federal sex crimes. If you read the text it seems a similar picture emerges in respect of other jurisdictions within the USA. Federal arrests in fact only accounted for 4% of all arrests.
No indication of if or how the internet was part of the offending behaviour. Neither are child sex offences separated out but the publication lists some of the initiatives and laws which lie behind some of the stats and it is quite clear that cyber and children are part of it.