vl.markPoint({filled: true})
.data(data)
.encode(
vl.x().fieldQ('Age').title("Age Group"),
vl.y().fieldQ('People').title("Count (Millions)").axis({format: '~s'}),
vl.color().fieldN('Sex').legend({title: "Sex"}).scale({
range: ['#fc89ff', '#4a90e2']
}),
vl.shape().fieldN('Year'),
vl.opacity().value(.7),
vl.size().value(50)
)
.width(600)
.title("U.S. Population in 1900 and 2000")
.render()