The following table details the book value and the fair value of financial instrument groups presented in the financial statements not in accordance with their fair value:
| As at December 31, 2017 | As at December 31, 2016 | ||
| Carrying amount | Fair value | Carrying amount | Fair value |
| $ millions | $ millions | $ millions | $ millions |
(1) The fair value of the shekel, euro, dollar and yuan loans issued bearing fixed interest is based on calculation of the present value of the cash flows in respect of the principal and the interest and is discounted at the market interest rates on the measurement date for similar loans having similar characteristics and is classified as Level 2 in the fair value hierarchy. The average discount interest as at December 31, 2017 for the shekel, euro and yuan loans was 2.4%, 1.7%, 6.1%
Note 24 - Financial Instruments and Risk Management (cont'd)
F. Fair value of financial instruments (cont'd)
and 5.6% respectively (December 31, 2016 for the shekel, euro, dollar and yuan loans – 3.3%, 2.3% and 4.2% and 5.6%, respectively).
(2) The fair value of the marketable debentures is based on the quoted stock exchange price and is classified as Level 1 in the fair value hierarchy.
(3) The fair value of the non‑marketable debentures is based on calculation of the present value of the cash flows in respect of the principal and the interest and is discounted at the Libor rate customary in the market for similar loans having similar characteristics and is classified as Level 2 in the fair value hierarchy. The average discount interest as at December 31, 2017 was 4.57% (December 31, 2016 – 4.98%)