I got curious and ran some numbers based on median values for home price, 30 year mortgage rates, and household income per FRED:
https://fred.stlouisfed.org/series/MSPUShttps://fred.stlouisfed.org/series/MORTGAGE30UShttps://fred.stlouisfed.org/series/MEHOINUSA672NFor transparency and a more valid comparison I used the earliest values available for a given year, and assumed 20% down payment since low down payments are a fairly recent option. The mortgage numbers were run through google's mortgage calculator to get monthly P/I based on a loan for 80% of purchase price and the interest rate in early January of each year.
1980- selling price was 63700, mortgage rate was 12.9%, and income was 21k. That spits out a Principal/interest payment of $557/mo or 32% of monthly income. Median selling price was 3 times median income.
1990- Selling price was 123900, mortgage rate was 9.8%, income was 57k. Monthly P/I was $854, or 17.9% monthly income. Median selling price was 2.17 times median income.
2000- Selling price was 165300, mortgage rate was 8.1%, income was 62,500. Monthly P/I was $978, or 18.8% monthly income. Median selling price was 2.64 times median income.
2010- Selling price was 222900, mortgage rate was 5.1%, income was 57,900. Monthly P/I was $969, or 20% monthly income. Median selling prices was 3.85 times median income.
2020- Selling price was 329000, mortgage rate was 3.6%, income was 69,000 (guessing slightly higher than 2019). Monthly P/I was $1196, or 20.8% of monthly income. Median selling price was 4.76 times median income.
Caveats:
-This is only the Principal and interest of the mortgage, so does not include insurance or property taxes.
-Real estate costs and incomes are both highly variable by location, so using a national median might not represent a given location very well.
-Mortgage rates can vary based on credit rating, etc
-Those making lower down payments would be paying more in P/I each month than my calculations, plus have the added cost of PMI. So a 5% down buyer in 2020 would actually be spending $1418/mo on P/I which is 24.6% monthly income, plus PMI and other associated costs.
Conclusions:
-incomes nearly tripled between 1980 and 1990,
and interest rates dropped which resulted in 1990 being a great year to buy, even with what we'd consider to be a really high interest rate today.
-general trends since 1990 have resulted in increasingly worse price:income ratio and increasing % of monthly income needed for housing each decade.