First, the boom from 2004 until 2008 wasn't evenly distributed at all - not that it's surprising. The disposable income of the top 10% grew 33% in four years while the income of other groups grew 21-25% (the "80-90%" income group added 25% to its real disposable income, the bottom 10% added 21%). This had the obvious effects that the income ratios between the top 10% and the rest fell.
Second, although the Gini coefficient has gone down from 29.6 in 2004 down to 23.6 in 2011 (based on incomes of the years 2003 and 2010), the main source of the increased equality, according to the Gini, is that the top 10% have lost all their income increase.
Third, the real disposable income of households has gone back to the level of 2004. There is basically no growth in real disposable income over 7 years! In the meanwhile, the debt of Icelandic households has grown by at least 20 percentage points if the ratio debt/GNP is examined. And the real disposable income is not adjusted for debt burden.
Graph 1: Real Disposable Income of Icelanders on fixed 2010 prices.
Graph 2: Since most of the income growth during the boom years was in the richest group, the ratio of other groups' income to the top-income group fell; Iceland was edging closer to a Plutonomy. The ratio bounced back after the collapse, basically because the top earners lost all theirs.
Graph 3: An index of real disposable income of different groups. The growth of the Real Disposable Income that took place during the boom years is all gone. In the meanwhile, a conservative estimate of Households' debt at year end 2011 was 117% of GNP compared to 98% in 2004.
Graph 4: Debt of Icelandic households according to book-value of debt. The face value is somewhat higher, especially after the 2008 collapse. Today's Icelanders have to pay 20% higher debt with the same real disposable income they had in 2004.