Fuzzy retirement math

See if you agree with following numbers from last year’s study from Aon Consulting and Georgia State University, as reported by the Associated Press:

“Someone with a gross income of $60,000, retiring at 65, would need $47,000, or 78 percent, to maintain the same standard of living. The reduction reflects expected changes in taxes and work-related expenses. The $47,000 could come from a mix of savings, Social Security and employer benefits.

The percentage needed is higher on either end of the salary scale. Those making $40,000 or less will need at least 85 percent of their income in retirement. Lower-paid employees save the least and, while working, pay the least in taxes as a percentage of income. So they spend more of their gross income while working and need a high percentage to maintain their lifestyle in retirement.

People earning $150,000 or more should plan to replace 84 percent or more of their income. They face relatively heavier taxes, in part, because the bulk of their Social Security benefits are taxable. Savings also need to be more substantial because Social Security makes up a smaller percentage of their necessary retirement income.
Those examples don’t include spending on Medicare or supplemental insurance, which would increase costs by thousands of dollars.