FACTS REGARDING THE FIELD OF IMPLEMENTATION OF THE EXTERNAL MONITORING returns, that are being operated entirely by the International Organisation for Migration (IOM), which show a decrease in relation with 2015 (6153). Total numbers are provided by the Greek Police regarding the nationality of the returned persons, from which the point arises that, from the total number of 13,439 forced removal operations, during 2017, the 11,161 cases concerned citizens of Albania, in other words, a percentage of 83%. Numerical data regarding administrative detention in view of return Regarding the administratively detained people, the Greek Police informed the Ombudsman that on 1.11.2017 a total of 2,598 persons were being held at Pre-removal Centres, which is a number overwhelmingly much greater (by 60%) than the respective number of 1,583 detained people in 2016 (see Graph 2). The respective number of immigrants being held for return in police cells on 1.11.2017 was 974 people, a fact that confirms the detention in interim places until a space can be found in the Pre-removal Centres, but also the great number of administratively detained people by the Greek police in total. The Ombudsman acknowledges the provision of data for detainees outside of Pre-removal centres in 2017, as an obvious example of transparency by the Greek Police. Nevertheless, he cannot but again re-emphasize that the 27% of the total number Chart 2 Detainees in Pre-removal Centres 2,598 1,583 November 2017 November 2016 15