pre_text: GasLog Ltd. and its Subsidiaries
  Notes to the consolidated financial statements (Continued)
  For the years ended December 31, 2017, 2018 and 2019
  (All amounts expressed in thousands of U.S. Dollars, except share and per share data) Credit risk Credit risk is the risk that a counterparty will fail to discharge its obligations and cause a financial loss and arises from cash and cash equivalents, short-term investments, favorable derivative financial instruments and deposits with banks and financial institutions, as well as credit exposures to customers, including trade and other receivables, dividends receivable and other amounts due from related parties. The Group is exposed to credit risk in the event of non-performance by any of its counterparties. To limit this risk, the Group currently deals primarily with financial institutions and customers with high credit ratings. For the year ended December 31, 2019, 70.0% of the Group’s revenue was earned from Shell (December 31, 2018 and December 31, 2017, 74.2% and 92.6%, respectively) and accounts receivable were not collateralized; however, management believes that the credit risk is partially offset by the creditworthiness of the Group’s counterparties. BG Group was acquired by Shell on February 15, 2016. This acquisition does not impact the contractual obligations under the existing charter party agreements. The Group did not experience significant credit losses on its accounts receivable portfolio during the three years ended December 31, 2019. The carrying amount of financial assets recorded in the consolidated financial statements represents the Group’s maximum exposure to credit risk. Management monitors exposure to credit risk, and they believe that there is no substantial credit risk arising from the Group’s counterparties. The credit risk on liquid funds and derivative financial instruments is limited because the counterparties are banks with high credit ratings assigned by international credit-rating agencies.
table: As of December 31,
table: 2018 2019
table: Cash and cash equivalents 342,594 263,747
table: Short-term investments 25,000 4,500
table: Trade and other receivables 20,244 24,900
table: Dividends receivable and other amounts due from related parties 33,395 573
table: Derivative financial instruments 15,188 4,001
question: Analyse this data from a financial earnings document. What was the change in short-term investments from 2018 to 2019?