vl.markLine({point:true})
.data(countries_with_year_as_dates.slice(0,20))
.encode(
vl.column().fieldN("country").title("Country"),
vl.x().fieldT("year").timeUnit("utcyear").axis({ tickCount: 5, title: "Year", format: "‘%y" }),
vl.y().fieldQ("life_expect").axis({ title: "Life expectancy" }),
)
.title("Life expectancy in Afghanistan and Argentina")
.render()