scatter = {
const scatterplot = vl.markPoint()
.data(countries)
.transform(vl.filter("datum.year == 1980 || datum.year == 1990 || datum.year == 2000"))
.encode(
vl.x().fieldQ("life_expect"),
vl.y().fieldQ("fertility"),
vl.tooltip(["life_expect", "fertility", "country"]),
vl.column().fieldN("year")
).title("life_expect x fertility")
return scatterplot.render()
}