Since another replier gave a book for 100 years, here's one of those... http://ageofem.com/ Though I imagine 50 years has a small but non-zero probability in Prof Hanson's distribution, and he's pretty careful of not seeming overly certain: "Conditional on my key assumptions, I expect at least 30% of future situations to be usefully informed by my analysis. Unconditionally, I expect at least 10%."