So far this year, the IRS has received 99 million tax returns and distributed an average refund of $2,794. If you still haven’t submitted your return, or filed an extension, you have until midnight to do so. Thankfully, there’s no such deadline for looking over these tax figures — as depressing as they might be:

1. The 400 highest income filers paid an average tax rate of 16.6 percent in 2007 (before the Great Recession). Dividends and net capital gains accounted for 73.4 percent of the adjusted gross income for these filers, explaining why their average effective tax rate is just a shade above the 15 percent preferential rate on unearned income.

2. Presidential candidate Mitt Romney, who has an estimated net worth between $190 million and $250 million, paid an effective tax rate of 13.9 percent in 2010 on $21.7 million in income because of the carried interest loophole and the preferential tax rates on capital gains and dividends.

3. In 2011, the top 1 percent of households by cash income received 75.1 percent of the benefit from the preferential treatment of capital gains and dividends. The middle class, meanwhile, received only 3.9 percent of that benefit.

4. Over the past 35 years, Congress has gradually lowered the top tax rate on capital gains from 40 percent in 1977 to the preferential rate of 15 percent today, courtesy of the Bush-era tax cuts. The Bush tax cuts also lowered the rate on qualified dividends—previously taxed as ordinary income—from 39.6 percent to just 15 percent.

5. The Bush tax cuts cost $2.6 trillion over the last decade, accounting for roughly half of the increase in the public debt over this period, while failing to generate a robust (or even mediocre) economic recovery.

6. Roughly half of the Bush tax cuts went to the highest-income 10 percent of earners, even though these earners captured more than 90 percent of national income gains between 1979 and 2007.

7. The top 1 percent of earners received 38 percent of the Bush tax cuts, despite capturing 65 percent of income gains during the Bush economic expansion (2002-2007).

8. Continuing the Bush-era tax cuts would cost $4.4 trillion over the next decade, which would single-handedly move the country from a sustainable to unsustainable fiscal path.

9. The additional tax cuts in Wisconsin Rep. Paul Ryan’s budget—beyond continuing the Bush tax cuts, which would be financed with deep spending cuts—have no offset and would lose $4.6 trillion in revenue over a decade, blowing a huge hole in the budget.

10. Massive, unaffordable tax cuts were also the currency of the Republican presidential primary race, with proposed tax cuts that would lose up to $900 billion annually—which at 4.9 percent of GDP would more than double projected budget deficits under a continuation of current policies—above and beyond the costly Bush tax cuts.

Follow Andrew Fieldhouse on Twitter: @A_Fieldhouse