[
  {
    "category": "atomic-and-nuclear",
    "count": 174
  },
  {
    "category": "conversions-and-adopted",
    "count": 40
  },
  {
    "category": "electromagnetic",
    "count": 74
  },
  {
    "category": "photometric",
    "count": 1
  },
  {
    "category": "physico-chemical",
    "count": 50
  },
  {
    "category": "universal",
    "count": 16
  }
]