1. A system comprising: one or more hardware processors; a computer-readable medium having instructions stored thereon, which, when executed by the one or more hardware processors, cause the system to: receive, via a computerized user interface implemented as a screen of a graphical user interface, a submission of a confidential data value of a confidential data type from a user, entered into a field of the screen of the graphical user interface, the previously submitted confidential data values having been encrypted on an external data source; determine, using the one or more hardware processors, a number of buckets for an empirical histogram of the confidential data values submitted to a computer system; compute, using the one or more hardware processors, the empirical histogram for the confidential data values having the determined number of buckets, the computing the empirical histogram including computing empirical histogram endpoints and associated fractions in each of the determined number of buckets; compute, using the one or more hardware processors, posterior distribution endpoints corresponding to the computed empirical histogram endpoints of the empirical histogram, the computing the posterior distribution endpoints including determining a posterior distribution for each cohort type in a set of cohort types having a small sample size, wherein a cohort is a grouping of multiple attributes of users; divide, using the one or more hardware processors, an interval between the posterior distribution endpoints into the determined number of buckets, producing a smoothed histogram based on the posterior distribution; determine, using the one or more hardware processors, a weight factor based on a ratio between a number of valid entries in a cohort of the confidential data values and a threshold used for smoothing, the threshold used for smoothing defining a level that differentiates between small sample sizes and large sample sizes; and perform, using the one or more hardware processors, linear interpolation of bucket endpoints for the empirical histogram and the smoothed histogram, using the weight factor to weight the empirical histogram.