Are there studies that identify the possible probabilistic and statistic distributions of Mandarin tones [either in general or in specific corpora]? I have developed some very general data eg Tone 1 occurs around 18% of the time, Tones 2 and 3 slightly higher than Tone 1, Tone 4 occurs > 40%, and the neutral is relatively low. But I'd like to obtain more detailed data and also theories as to how experts view tones in probability [if this style can even be accomplished]. Would Bayesian probabilities not be appropriate?