Plotting a graph with several observations per year

[Linus Ze]

Hello everyone.

I am currently working on a data set with trade values broken down into single transactions and have the task to make descriptive graphs.

The problem I face is that there are several values per year. It is structured like this (with about 50,000 observations on 120 countries):

Variables: country years trade_total

Country1	2010	Value 1
Country1	2010	Value 2
Country1	2011	Value 3
Country1	2011	Value 4
Country2	2010	Value 5
Country2	2010	Value 6
Country2	2011	Value 7
Country2	2011	Value 8

So I wanted to do line graphs showing the total value of transactions per year and per country using a code like

twoway line trade_total year, by(country)

But these graphs turn out very bad, because there are several observations per year.

I'm a beginner in stata, so excuse my missing expertise, I didn't find any posts regarding this exact problem when it comes to plotting.

[Nick Cox]

Your trade_total variable itself should be summed, as in

egen double trade_sum = total(trade_total), by(country year) 
egen tag = tag(country year)

However, even a plot

line trade_sum year if tag, by(country)

will suffer because of the number of countries, so at best this code will solve one problem and leave you with all the other problems.