Enables computation of epidemiological statistics where e.g. counts or mortality rates of the reference population are used. Currently supported: excess hazard models, rates, mean survival times, relative survival, as well as standardized incidence and mortality ratios (SIRs/SMRs), all of which can be easily adjusted for e.g. age. Fast splitting and aggregation of 'Lexis' objects (from package 'Epi') and other computations achieved using 'data.table'.