Plot.plot({
color: {
domain: ["Serology", "Surveys"],
legend: true},
marks: [
Plot.rectY(bls, Plot.binX({y: "count"}, {x: "Survey_date", fill: "brown", opacity: 0.5, insetLeft: 5})),
Plot.rectY(sero, Plot.binX({y: "count"}, {x: "COLLECTED", fill: "#6A5ACD", opacity: 0.5, insetRight: 5})),
Plot.ruleY([0]),
Plot.line(nsw, {x: "Date", y: d => (d.per_1000*60), curve: "basis", strokeWidth: 0.6})
]
})