Data on outstanding confiscation orders is published annually by HMCTS as part of their trust statement. The latest trust statement was published on 17 July 2018 (https://www.gov.uk/government/publications/hm-courts-tribunals-service-trust-statement-2017-to-2018), indicating a gross value of confiscation order debt at £1,961million, of which £152million is considered recoverable.
Data on asset recovery performance under the Proceeds of Crime Act 2002 is published annually by the Home Office. The latest data, showing asset recovery performance year on year from 2013-2018, was published on 13 September 2018 (https://www.gov.uk/government/collections/asset-recovery-statistics).
Data on asset recovery performance at the National Crime Agency is published annually in their annual report, which is published according to financial year.