"European Union (EU) statistics currently available on crime and criminal justice reflect the diversity of policing and legal systems within the EU. Comparisons of crime statistics between Member States should focus on trends over time, rather than directly comparing levels between countries for a specific year, given that the data can be affected by a range of factors, including different levels of criminalisation, the efficiency of criminal justice systems and police recording practices; furthermore, it is likely that a relatively high proportion of crime remains unrecorded. Work is in progress to improve the comparability of crime statistics across the EU Member States." (Quoted from the statistics)