function getAllCurrencyTicker() public view returns(string) {
    string memory _tickers = "{";
    for (uint i = 0; i < currencyTicker.length; i++) {
      _tickers = strConcat(_tickers, strConcat("\"", bytes32ToString(currencyTicker[i]), "\":"), uint2str(currencyList[currencyTicker[i]].usd), (i+1 < currencyTicker.length) ? "," : "}");
    }
    return _tickers;
  }