vl
.markArea()
.data(data.filter(x => (x.states === statesFilter)))
.transform(vl.density('firearm_death_rates').bandwidth(0.3))
.encode(
vl
.x()
.fieldQ('value')
.title('Firearm Death Rate'),
vl
.y()
.fieldQ('density')
.title('Density')
)
v1.markRule({color: 'red'})
.encoding( vl.x().fieldQ('value'))
.title("Density of Firearm Death Rates")
.render()