How many roman emperors ruled during the 50-year period covered by this chart how many died a natural death what was the most frequent cause of death of these men?

To accurately answer your question, I would need more specific details about the chart you are referring to, such as the time period it covers and the emperors included. However, generally speaking, during any given 50-year period of the Roman Empire, several emperors may have ruled, with some historically documenting natural deaths. The most frequent cause of death for many Roman emperors tends to be assassination or violent overthrow, although natural causes such as illness were also common. Please provide more context for a precise answer.