This is my code:

ggplot(aes(year,gdpPercap),data = gapminder::gapminder) + 
          geom_point()
ggplot(aes(year,gdpPercap),data = gapminder::gapminder) + 
          geom_point(stat = 'sum')

Why the plot is almost the same? The only difference is that the dots are bigger.

But the plot should be different as I asked for the "sum" tranformation.