How to indicate proportion of tasks in each of several sequential stages?

I have many (thousands) of tasks, each currently in one of 5 sequential stages. (So every task goes through the exact same sequence, but concurrently, so that some are at a different stage from others). How should I indicate to the user the proportion of tasks in each stage? The simple answer would be a pie chart, but I don't know if there is a better option, given that the stages are sequential, and a pie chart doesn't convey any sort of sequence.