Hi guys, I need your help!

I have to replicate a table in which there are some variables ( gdp growth, labor share, etc)

I have a database that cointains for each country the times series ( 1960-2000) of the base variables.

How can I compute a unique value starting from a time series??

For example:

I need to compute the Capital Share ( K / Y ) of USA

In the database I have the time serie of K and the time serie of Y

If I make K / Y with R , I get a time series as a result, but I need instead a single number ( as in the table that I have to replicate )

Should I make an average of all the observations in K and an average of all the observations in Y an then make the ratio?

Or should I compute the difference from the first observation and the last one for both variables and then make the ratio?

thanks to anyone who will help me