The price of gas

Could someone please explain this to me:

Last year the oil cost 145 USD per barrel, and 1 USD was worth 6 SEK. One barrel cost 870 SEK.

Today the oil costs 70 USD per barrel, and 1 USD is worth 7,70 SEK. One barrel costs 539 SEK.

So why the hell is the gas price virtually the same (13 SEK/liter and increasing week by week versus an "all time high" of 14 SEK last year)? Yes, I know 0,4 SEK is contributed to an increase of the gas tax, but there's still a pretty big gap here, and God only knows what the gas price will look like once the oil reaches 145 again...