What percentage constitution does total non-current borrowings hold in the total opening balance?
{"": {"OPENING": "BALANCE", "NONCASH": "MOVEMENTS", "NET CASH": "MOVEMENTS", "CLOSING": "BALANCE"}, "2019": {"OPENING": "$M", "NONCASH": "$M", "NET CASH": "$M", "CLOSING": "$M"}, "Current, unsecured -- Short-term money market loans": {"OPENING": 16, "NONCASH": 2, "NET CASH": 21, "CLOSING": 39}, "Current, unsecured -- Bank loans": {"OPENING": 88, "NONCASH": 5, "NET CASH": 142, "CLOSING": 235}, "Current, unsecured -- Securities": {"OPENING": 500, "NONCASH": "\u2013", "NET CASH": -500, "CLOSING": "\u2013"}, "Current, unsecured -- Total current borrowings": {"OPENING": 604, "NONCASH": 7, "NET CASH": -337, "CLOSING": 274}, "Noncurrent, unsecured -- Bank loans": {"OPENING": 540, "NONCASH": 36, "NET CASH": 102, "CLOSING": 678}, "Noncurrent, unsecured -- Securities": {"OPENING": 1668, "NONCASH": 110, "NET CASH": 400, "CLOSING": 2178}, "Noncurrent, unsecured -- Unamortised borrowing costs": {"OPENING": -9, "NONCASH": 5, "NET CASH": "\u2013", "CLOSING": -4}, "Noncurrent, unsecured -- Finance leases": {"OPENING": "\u2013", "NONCASH": 6, "NET CASH": -3, "CLOSING": 3}, "Noncurrent, unsecured -- Total noncurrent borrowings": {"OPENING": 2199, "NONCASH": 157, "NET CASH": 499, "CLOSING": 2855}, "Noncurrent, unsecured -- Total": {"OPENING": 2803, "NONCASH": 164, "NET CASH": 162, "CLOSING": 3129}}
total_non_current_borrowings = df["Noncurrent, unsecured -- Total noncurrent borrowings"]["OPENING"]
total_opening = df["Noncurrent, unsecured -- Total"]["OPENING"]
answer = total_non_current_borrowings / total_opening * 100.0