No, it is not normal for 10% of the coountry to power half the spending. Just think about that statistic for a second. Spending includes groceries, services, and other continual needs. A few private jets can't outspend millions of people buying food.
>No, it is not normal for 10% of the coountry to power half the spending.
Yet, if you look at your chart, it was 40% in 1989s and have been slowly edging up. While 40% is a smaller number than 50%, you can make the same argument about 40% not being "normal", yet society has been chugging along just fine.
What was the historical trend? Otherwise you can't draw much from just "49.2%" alone, aside from a vague sense that stuff should be fairer.