In 1980, the average American CEO made 45 times what their employees made. By 2003, they were making 254 times what their workers made. After 8 years of Bush, they now make over 400 times what their average employee makes. How this can happen at publicly held companies is beyond reason. In Britain, the average CEO makes 28 times what their average employee makes. In Japan, it's only 17 times!
Whilst Mr Moore doesn't provide a reference for these figures, they are similar to other numbers being bandied around. If the average CEO earns 400 times what their average employee makes, then there must be some CEOs who earn far more than that. Even at a ratio of 400, that means that the boss earns in one day more than his (or rarely her) average employee earns in a whole year.
Wikipedia has a comprehensive (and fully referenced) table of countries by income equality. This introduced me to the Gini coefficient, which is a scientific method of comparing income inequalities between countries. That page also has a nice chart of Gini indices over time for selected countries, which shows that the UK has been steadily becoming less equal over the last half century, whilst Norway has been going the opposite way.