Biology — Chart: Atmospheric Gases

{
  "$schema": "https://vega.github.io/schema/vega-lite/v5.json",
  "description": "Composition of dry air",
  "data": {"values": [
    {"gas": "Nitrogen", "percent": 78.1},
    {"gas": "Oxygen", "percent": 20.9},
    {"gas": "Argon", "percent": 0.93},
    {"gas": "CO2 + trace", "percent": 0.07}
  ]},
  "mark": "arc",
  "encoding": {
    "theta": {"field": "percent", "type": "quantitative"},
    "color": {"field": "gas", "type": "nominal", "title": "Gas"}
  }
}