attr('d', d3.arc()
    .innerRadius(100)         // This is the size of the donut hole
    .outerRadius(radius)
  )
  .attr('fill', d => color(d.data[0]))
  .attr("stroke", "black")
  .style("stroke-width", "2px")
  .style("opacity", 0.7)
</script></xmp></code></pre>
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          </div>
        </div>
      </div>
    </section>
    <br />

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    <!-- ============================ RELATED BLOCKS ==================