REUTERS Natural gas reserves in Ukraine&#39;s underground storage facilities (USFs) have increased by 86.3%, or by 6.4 billion cubic meters (bcm), to 13.85 bcm since April 9, when Ukraine started building up its gas stocks. Some 1.014 bcm of gas was injected into the USFs on August 1-18, 2018, according to the state-run gas transport system operator Ukrtransgaz. Read alsoNaftogaz raises purchase price of natural gas Natural gas reserves in Ukraine&#39;s USFs as of August 18, 2018, were estimated at 13.85 bcm, which was 1.9%, or 263 million cubic meters (mcm) down from 14.1 bcm reported as of August 18, 2017. Ukrainian gas imports on August 1-18, 2018, totaled 740.6 mcm, including 400 mcm via Slovakia, 293.5 mcm via Hungary, and 47.3 mcm via Poland. Domestic gas output over the period under review stood at 1.03 mcm, while gas transit shipments totaled 4.275 bcm, it said. The country&#39;s USFs were filled by 44.7% as of Saturday, August 18. As UNIAN reported earlier, 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.