[en] Radiation Dosimetry and Radiobiology Unit of the Institute for Medical Research and Occupational Health (IMROH) performs the service of dosimetry for approximately 2000 users. The number of users has gradually risen from 1000 to nearly 2000 persons in an interval of two years (2011 -2012). Most users work in medicine (75 %) while others are in research (14 %) and industry (11 %). H_p(10) distribution over the two years of consideration was mainly consistent. A deviation from this consistency was observed during the first three months of the year 2012. The maximum H_p(10) and average H_p(10) distributions measured for the months in question were much higher than for any other month under consideration. The reason for this deviation was one exposed person who worked in the field of interventional radiology, a field within which worker spent much more time exposed to sources of ionizing radiation than recommended. There was a clear drop in the measured H_p(10) after the first three months of 2012 because the person responsible for the high measurements had to stop working in the field of ionizing radiation. Thus, the measured H_p(10) values for April 2012 and subsequent months were significantly lower (consistent with all other months under consideration). The evaluation of the H_p(10) distribution is very important because any deviations in the expected effective doses for a certain occupation or field of interest may prove significant from the radiation protection point of view.(author)