Addendum: UK inequality over time

Even though social mobility has nothing to do with economic inequality per se (in fact, increased social mobility can induce inequality), here is another addendum to yesterday's post I came up with Velichka today (click to enlarge):

The left plot is from the official UK stats website, showing the evolution of the Gini over time. This plot is misleading in two ways. First, the header "Income inequality remains stable" does not refer to the entire period 1983-2009 but rather to the period "since 2005/2006 [where] the level of inequality was relatively stable". Since changes in distribution evolve very slowly anyway, this is a somewhat redundant thing to say for a three year period. Second, the data only goes back to 1983, showing us half the story. It also demonstrates once more the perils of statistical framing.  

The right plot is based on the exact same calculation and source but goes back as far as 1962. While the rise in the Gini coefficient by 10% points between 1980 and 2000 may not seem that obvious if looking at the limited 1983-2009 period, the stark increase becomes very obvious once gauged against the pre-1983 trend. Needless to say, the structural break in 1979 coincides with the 1979 election, where Thatcher became Prime Minister.