What if I had invested it?

A lump sum, or so much a month, from any year to now — in today's money, so the answer means something.

For instance

What you can put after the amount

SeriesCoversWhat it is
/sp5001975–2024the S&P 500
/house1953–2025a UK house
/cash1975–2026cash at Bank Rate
/60-401975–2024a 60/40 portfolio
/80-201975–2024an 80/20 portfolio
/rpi1948–2025just keeping up with prices
/10percentanya flat rate you choose
/vls60, /vls801975–2024fund names, pointed at the matching backtest