Of internal migrants, 23% reported that employees of citizen service centres (Tsentri obslujivania naselenia) and medical personnel, for instance, took advantage of their lack of local registration to ask for a bribe. Internal migration data is tracked by the Agency for Statistics, using information supplied by the Migration Policy Committee and the Public Service Centres that collect registration records. Unreliable figures for registered migrants pose problems in calculating the real number of people living in a given place. Official statistics do not always reflect the number of people for whom public services are needed.