Show current voice rates

Example response

{
  "rates": [
    {
      "block": "6/6",
      "destination": "United States - Fixed - USA Fixed/mobile",
      "prefix": "1",
      "price": 0.00675
    },
    {
      "block": "6/6",
      "destination": "United States - Fixed - New York",
      "prefix": "1212",
      "price": 0.00675
    }
  ]
}