A dataset in a format similar to `initial_data`. This dataset must contain the variables "state_from", which is the status at the beginning of the transition (say smoker in 2010),
"state_to", which is the status at the end of the transition (say ex-smoker in 2011) and "tran_Year", which is an integer variable that is equal
to the number of transitions. "tran_Year" == 1 means that the transition occurs from 2010 to 2011, "tran_Year" == 2, from 2011 to 2012, up to
the total number of transitions