Company	2014	2015	2016	2017	2018	∆ 2018/2017 (%)
Slavneft	(5,072)	9,265	13,916	10,347	15,025	45.2
Messoyakhaneftegaz	–	–	(947)	9,976	28,172	182.4
Arcticgas	(1,809)	11,913	14,472	19,861	40,451	103.7
Northgas	–	3,466	3,009	3,433	3,699	7.7
Other companies	575	312	3,666	1,887	3,357	77.9
Total revenue	(6,306)	24,956	34,116	45,504	90,704	99.3

The Group’s profit share in Slavneft increased y-o-y due to higher crude oil prices, while in Messoyakhaneftegaz – as a result of both, higher prices and production growth. The Group’s profit share in Arcticgas grew y-o-y following the production growth, higher crude oil prices and lower financial expenses in line with the optimisation of the debt portfolio, and the increase of Group’s share in Arcticgas from 46.67% to 50% from 21 March 2018.

Other income and expenses

Other expenses, which in 2018 mainly included disposal and write-offs of non-current assets, grew by 2.6 times y-o-y.

Other financial items

Foreign exchange gains (losses) are primarily attributable to the revaluation of the portion of the Group’s debt portfolio which is denominated in foreign currencies.