The 90% number is not true. Although the percentage of diesel cars has gone up dramatically, it is not that high. In 2011 only 17% of cars were diesel driven[1]. During the first two months of 2013, 63% of new cars were diesel[2].

[1] http://www.scb.se/Statistik/TK/TK1001/2011A01B/FORDON_2011_v... [2] http://www.scb.se/Statistik/TK/TK1001/2013M02/Trafikanalys_1...