It looks like it's been pretty stable for three years, after what looks like a spike in the end of 2021.
I can't see past 5Y without paying, so I don't know if the past three years was an abnormal low, or if that's the regular cost.
2022 was abnormally high, caused largely by the disruption of gas supplies to Western Europe after sanctions on Russian gas and the destruction of the Nordstream gas pipeline.
2022 was abnormally high, caused largely by the disruption of gas supplies to Western Europe after sanctions on Russian gas and the destruction of the Nordstream gas pipeline.