People who do not know better do repeat mistakes, sometimes over and over. It is not unheard of for some to have been disfellowshipped and/or reproved several times. Given that most people are disfellowshipped for "sins of the flesh" - and that relatively few are disfellowshipped for apostasy - the return rate would probably be higher among those who have "broken" moral rules than those who have apostasized from the organization.
Whether the ratio of those who return to those who stay away changes from year to year is an empirical question. While the organization would probably have on hand data that shows the annual number of reinstatements, they have yet to publish the data in their literature. On the other hand, at times they have published data in their literature on the annual number of people disfellowshipped.
