I have a dataset with quarterly data, and among the individuals I am studying, there are those who experience the event of interest, or right-censored ones (i.e., those who disappear from the study after their last quarter of observation without any further data provided in the future, or live until the end of the study period by providing data until the last day of the study period). For those who experience the event, I have a record of the last quarter of observation prior to the event date (for example, individual X dies on 04/15/2010, and their last recorded observation is on 03/31/2010).