In addition to the four proficiency levels, there are three additional categories (no computer experience, failed ICT core and opted out) for those adults who were not able to demonstrate their proficiency in this domain due to lacking the basic computer skills needed to sit the assessment. See note 1 for Figure 2.8. The sample for the Russian Federation does not include the population of the Moscow municipal area. For more detailed results for each category, see corresponding table mentioned in the source below.