1. A method for monitoring global crude oil quality comprising: obtaining at least one sample of a crude oil representative of the current quality of the crude oil; analyzing the at least one sample of the crude oil and generating characterization data based upon the analyzing of the at least one sample by laboratory distillation, spectroscopic techniques, or a combination of spectroscopic techniques and physical inspections; estimating values of properties of an assay of the crude oil by analyzing the generated characterization data from the at least one sample to form an estimated assay; storing the estimated values of the properties of the estimated assay in a database; determining deviations of the values of the properties of the estimated assay for the crude oil from the values of the properties of a known recommended assay for crude oil having a known quality, wherein the values of the properties of the known recommended assay are stored in the database wherein the known recommended assay is a single representation of yields and qualities used to characterize current crude oil quality; determining a statistical significance of the deviations of the values of the properties of the estimated assay from the values of the properties of the recommended assay to determine if the crude oil quality of the at least one sample is different from the quality of the recommended assay; generating a new recommended assay for the crude oil if the deviations of the values of the properties of the estimated assay from the values of the properties of the recommended assay are significant; and storing new recommended assay in the database.