My back test shows this strategy consistently generates a CAGR on the order of 9% with a maximum drawdown of 3%. This does not pass the common sense test for me - something must be wrong. It doesn't matter what period or duration I run my back-test - 3 years, 10 years, 20 years - it's all similar.

What's my flaw? I do not own any commercial backtesting tool - if someone has one that could easily run this and post their results, I would be forever grateful.