REUTERS Natural gas reserves in Ukraine&#39;s underground storage facilities (USFs) have increased by 2.25 times, or by 9.24 billion cubic meters (bcm), to 16.68 bcm since April 9, when Ukraine started building up gas stocks. Some 444.5 million cubic meters (mcm) of gas was injected into the USFs on October 1-14, 2018, according to the state-run gas transport system operator Ukrtransgaz. Natural gas reserves in Ukraine&#39;s USFs as of October 14, 2018, were estimated at 16.68 bcm, which was 0.6% down from 16.77 bcm reported as of October 14, 2017. Read alsoNaftogaz pays almost $3.41 bln in taxes Ukrainian gas imports on October 1-14, 2018, totaled 411 mcm, including 213.5 mcm via Slovakia, 167.262 mcm via Hungary, and 30.2 mcm via Poland. Domestic gas output over the period under review stood at 815.6 mcm, while gas transit shipments totaled 2.96 bcm, it said. The country&#39;s USFs were filled by 53.9% as of Sunday, October 14. As UNIAN reported, the National Joint-Stock Company Naftogaz of Ukraine earlier said that there were enough natural gas reserves in Ukrainian underground storage facilities to enter the 2018 2019 heating season. Ukraine entered 2018 with 14.7 bcm of gas in its USFs, which was the largest gas stock as of the beginning of the year in the past five years.