Countries where the most spoken language is English according to CLDR territoryInfo.json.

```
{
  "AC": "99%",
  "AG": "86%",
  "AI": "95%",
  "AU": "96%",
  "BB": "100%",
  "BE": "59%",
  "BM": "92%",
  "BS": "100%",
  "BW": "81%",
  "BZ": "100%",
  "CA": "86%",
  "CK": "95%",
  "CX": "63%",
  "DG": "99%",
  "DM": "94%",
  "ET": "43%",
  "FJ": "94%",
  "FK": "96%",
  "FM": "57%",
  "GB": "99%",
  "GD": "96%",
  "GG": "100%",
  "GI": "80%",
  "GM": "40%",
  "GU": "91%",
  "GY": "100%",
  "IE": "98%",
  "IM": "100%",
  "IO": "100%",
  "JE": "95%",
  "JM": "98%",
  "KI": "100%",
  "KN": "98%",
  "KY": "98%",
  "LC": "90%",
  "LR": "83%",
  "MH": "93%",
  "MP": "97%",
  "MS": "66%",
  "MW": "63%",
  "NF": "76%",
  "NG": "53%",
  "NR": "98%",
  "NU": "95%",
  "NZ": "98%",
  "PH": "64%",
  "PN": "85%",
  "SB": "100%",
  "SG": "93%",
  "SH": "69%",
  "SX": "68%",
  "SZ": "80%",
  "TA": "99%",
  "TC": "98%",
  "TK": "100%",
  "TT": "88%",
  "UM": "100%",
  "US": "96%",
  "VC": "96%",
  "VG": "98%",
  "VI": "75%",
  "ZA": "31%"
}
```

Script used:
```js
let territoryInfo = require('./territoryInfo.json')

let ret = Object.assign(...Object.entries(territoryInfo.supplemental.territoryInfo)
.map(([country, data])=> (
  [
    country,
    Object.entries(data.languagePopulation || {})
    .map(([language, data]) => (
      [language, +data._populationPercent]
    ))
    .sort((a, b) => b[1] - a[1])
    [0]
  ]
))
.filter(([country, data]) => data)
.filter(([country, [language, percent]]) => language === "en")
.map(([country, [language, percent]]) => ({[country]: `${percent}%`})))


console.log(JSON.stringify(ret, null, 2));
```