How to know if the data is censored in a survival analysis using r

Question

I have a data set that looks like this:

id <- c(1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 3)
year <- c(1990, 1991, 1992, 1989, 1990, 1991, 1992, 1993, 1989, 1990