DATA ANALYSIS: COEFFICIENT OF VARIATION OR STANDARD DEVIATION?

Should I use the coefficient of variation or the standard deviation if I am interested in whether the differences in GDP Per capita between European countries have increased or decreased? I want to know how dispersed the income is among countries in Europe.

Let's say that I find in my standard deviation that dispersion of income has increased since 2000, but when I use the coefficient of variation my values do not show an increase in in the dispersion of income since 2000, the graph shows a rather stable line.

Need to know: The mean GDP per capita has actually increased since 2000.

-Which of these methods and assessment is right? the coefficient of variation or the standard deviation?

-Why?