We have mortality data over five years.. What is the best way to analyse time trends in these data? Which is the best statistical software to study these trends?
R package is good for statistical analysis, what are are suggesting are also good enough but it depends on the objective and what kind of analysis you are looking for.
I also think like Kumar, however Kumar did not mention the name of the R packages. you may use R packages like zyp, trend for detecting trend in time series data.