Usability, most often defined as the ease of use and acceptability of a system, affects the users' performance and their job satisfaction when working with a machine. Therefore, usability is a very important aspect which must be considered in the process of a system development. The paper presents several numerical data related to the history of the scientific research of the usability of information systems, as it is viewed in the information provided by three important scientific databases, Science Direct, ACM Digital Library and IEEEF Xplore Digital Library, at difer- ent queries related to this field.