As of December 31
As of December 31
2019
2018
Total credit facility
$300,000
$300,000
Balance outstanding
$99,700
$50,000
Standby letters of credit
$1,800
$1,940
Amount available
$198,500
$248,060
Weighted-average interest rate
3.25%
3.10%
Commitment fee percentage per annum
0.23%
0.20%
notes to consolidated financial statements -in thousands except for share and per share data .
note 12 — debt .
long-term debt was comprised of the following : .
on february 12 2019 we entered into an amended and restated five-year credit agreement with a group of banks -the " credit agreement " to extend the term of the facility .
the credit agreement provides for a revolving credit facility of $ 300000 which may be increased by $ 150000 at the request of the company subject to the administrative agent ' s approval .
this new unsecured credit facility replaces the prior $ 300000 unsecured credit facility which would have expired august 10 2020 .
borrowings of $ 50000 under the prior credit agreement were refinanced into the credit agreement .
the prior agreement was terminated as of february 12 2019 .
the revolving credit facility includes a swing line sublimit of $ 15000 and a letter of credit sublimit of $ 10000 .
borrowings under the revolving credit facility bear interest at the base rate defined in the credit agreement .
we also pay a quarterly commitment fee on the unused portion of the revolving credit facility .
the commitment fee ranges from 0 .
20 % to 0 .
30 % based on our total leverage ratio .
the revolving credit facility requires among other things that we comply with a maximum total leverage ratio and a minimum fixed charge coverage ratio .
failure to comply with these covenants could reduce the borrowing availability under the revolving credit facility .
we were in compliance with all debt covenants at december 31 2019 .
the revolving credit facility requires that we deliver quarterly financial statements annual financial statements auditor certifications and compliance certificates within a specified number of days after the end of a quarter and year .
additionally the revolving credit facility contains restrictions limiting our ability to : dispose of assets ; incur certain additional debt ; repay other debt or amend subordinated debt instruments ; create liens on assets ; make investments loans or advances ; make acquisitions or engage in mergers or consolidations ; engage in certain transactions with our subsidiaries and affiliates ; and make stock repurchases and dividend payments .
interest rates on the revolving credit facility fluctuate based upon the libor and the company ’ s quarterly total leverage ratio .
we have debt issuance costs related to our long-term debt that are being amortized using the straight-line method over the life of the debt .
amortization expense for the twelve months ended december 31 2019 was approximately $ 163 and $ 185 in 2018 and 2017 .
these costs are included in interest expense in our consolidated statement of earnings .
we use interest rate swaps to convert the revolving credit facility ' s variable rate of interest into a fixed rate on a portion of the debt as described more fully in note 13 " derivatives .
" these swaps are treated as cash flow hedges and consequently the changes in fair value were recorded in other comprehensive earnings .

Question: How did the company convert the revolving credit facility's variable rate of interest into a fixed rate on a portion of the debt?

Question: What was the amortization expense for the twelve months ended December 31, 2019 in 2018?

Question: What was the total credit facility in 2019?

Question: How many years did the Weighted-average interest rate exceed 3%?

Question: What was the change in Balance outstanding between 2018 and 2019?

Question: What was the percentage change in the Standby letters of credit between 2018 and 2019?