 The report also noted that there were changes to the method used to estimate vehicle mileages in 1995 which would affect direct comparisons of figures spanning this year.The Department for Transport acknowledged in their report for the year 2008 that a considerable proportion of non-fatal casualties are not known to the police.Based on additional sources including hospital records, surveys and compensation claims they estimate that the total number of road casualties in Great Britain each year is nearer to 800,000 [although this figure itself may be influenced by the growth in the so-called 'compensation culture'].