8. Debt and Interest Rate Swap
Debt The carrying amount of the Company's long-term debt consists of the following:
On May 12, 2017, the Company entered into a credit agreement with certain lenders and a collateral agent in connection with the acquisition of Exar (Note 3). The credit agreement provides for an initial secured term B loan facility (the “Initial Term Loan”) in an aggregate principal amount of $425.0 million. The credit agreement permits the Company to request incremental loans in an aggregate principal amount not to exceed the sum of $160.0 million (subject to adjustments for any voluntary prepayments), plus an unlimited amount that is subject to pro forma compliance with certain secured leverage ratio and total leverage ratio tests. Incremental loans are subject  to certain additional conditions, including obtaining additional commitments from the lenders then party to the credit agreement or new lenders.
Loans under the credit agreement bear interest, at the Company’s option, at a rate equal to either (i) ab ase rate equal to the highest of (x) the federal funds rate, plus 0.50%, (y) the prime rate then in effect and (z) an adjusted LIBOR rate determined on the basis of a one- three- or six-month interest period, plus 1.0% or (ii) an adjusted LIBOR rate, subject to a floor of 0.75%, in each case, plus an applicable margin of 2.50% in the case of LIBOR rate loans and 1.50% in the case of base rate loans. Commencing on September 30, 2017, the Initial Term Loan will amortize in equal quarterly installments equal to 0.25% of the original principal amount of the Initial Term Loan, with the balance payable on the maturity date. The Initial Term Loan has a term of seven years and will mature on May 12, 2024, at which time all outstanding principal and accrued and unpaid interest on the Initial Term Loan must be repaid. The Company is also required to pay fees customary for a credit facility of this size and type.
The Company is required to make mandatory prepayments of the outstanding principal amount of term loans under the credit agreement with the net cash proceeds from the disposition of certain assets and the receipt of insurance proceeds upon certain casualty and condemnation events, in each case, to the extent not reinvested within a specified time period, from excess cash flow beyond stated threshold amounts, and from the incurrence of certain indebtedness. The Company has the right to prepay its term loans under the credit agreement, in whole or in part, at any time without premium or penalty, subject to certain limitations and a 1.0% soft call premium applicable during the first six months for the loan term. The Company exercised its right to prepay and made aggregate payments of principal of $213.0 million to date through December 31, 2019.
The Company’s obligations under the credit agreement are required to be guaranteed by certain of its domestic subsidiaries meeting materiality thresholds set forth in the credit agreement. Such obligations, including the guaranties, are secured by substantially all of the assets of the Company and the subsidiary guarantors pursuant to a security agreement with the collateral agent.
The credit agreement also contains customary events of default that include, among other things, certain payment defaults, cross defaults to other indebtedness, covenant defaults, change in control defaults, judgment defaults, and bankruptcy and insolvency defaults. If an event of default exists, the lenders may require immediate payment of all obligations under the credit agreement, and may exercise certain other rights and remedies provided for under the credit agreement, the other loan documents and applicable law.
As of December 31, 2019 and 2018, the weighted average effective interest rate on long-term debt was approximately4 .9% and 4.6%, respectively.
The debt is carried at its principal amount, net of unamortized debt discount and issuance costs, and is not adjusted to fair value each period. The issuance date fair value of the liability component of the debt in the amount of $398.5 million was determined using a discounted cash flow analysis, in which the projected interest and principal payments were discounted back to the issuance date of the term loan at a market interest rate for nonconvertible debt of 4.6%, which represents a Level 2 fair value measurement. The debt discount of $2.1 million and debt issuance costs of $6.0 million are being amortized to interest expense using the effective interest method from the issuance date through the contractual maturity date of the term loan of May 12, 2024.
During the year ended December 31, 2017, the Company recognized amortization of debt discount of $0.2 million and debt issuance costs of $0.6 million to interest expense.
The approximate fair value of the term loan as of December 31, 2019 and 2018 was $214.6 million and $268.1 million, respectively, which was estimated on the basis
of inputs that are observable in the market and which is considered a Level 2 measurement method in the fair value hierarchy.
As of December 31, 2019 and 2018, the remaining principal balance on the term loan was $212.0 million and $262.0 million, respectively. The remaining principal
balance is due on May 12, 2024 at the maturity date on the term loan.
Table:
 | December 31, 2019 | December 31, 2018
 | (in thousands) | 
Principal | $212,000 | $262,000
Less: |  | 
Unamortized debt discount | (1,328) | (1,630)
Unamortized debt issuance costs | (3,763) | (4,613)
Net carrying amount of long-term debt | 206,909 | 255,757
Less: current portion of long-term debt | — | —
Long-term debt, non-current portion | $206,909 | 255,757


Question: What is the average Unamortized debt discount for 2018 and 2019?
Answer: -1479
Calculation: -(1,328 + 1,630) / 2