A great little resource to see roughly how interest rates and 5-year expected annual growth rates effect earnings multiples.
The current 10-year treasury: 2.58
Expected 5-year average annual growth of S&P 500: 5%
(3% GDP + 2% inflation nominal 5% growth)
That hypothetically would leave us with somewhere in between 21-47x earnings. This by no means is a perfect matrix with correlation to actual results but a hypothetical scenario.