title: Formatting a number as a percentage in d3
body: <p>currently using Superset and trying to format the y-axis of a graph to show the number as a percentage.</p>
  
  <p>Values are</p>
  
  <p>0.7, 0.75, 0.9, 1.2, 1.21 and so on. I'm looking to format these as 0.70%, 0.75%, 0.90%, 1.20%, 1.21% etc. I'm having trouble formatting it in this way. When I use the '.2%' it returns two decimal places, ie. 1.21 turns into 121.00%. Using ',0.01' will return 1.2, 1.21 etc but when adding the percentage to the end, it doesn't show it - also, it doesn't add the second decimal place when it doesn't exist.</p>
  
  <p>Anyone know how to format 2 point decimal places in d3 (specifically for superset, which will only take a string rather than code)</p>