We know 70% of households don’t itemize deductions, that there are 117 million households, and that 34% of all households (42 million) rent. Assuming all renters take the standard deduction, that means 40 million owner households take the standard deduction and 35 million owner households itemize. We also know that 30%, or 21 million, households own their homes debt free. This means, at most, 74% of homeowners with a mortgage itemize.