An Annual Return of -10% or 20% ... how often?
This spreadsheet ("sorta_ATP") considers the data located in columns A, B and C.
(Example: Trimark Mutual Fund, daily values, from Jan 1/97 to Nov 26/99).
You select the time period (say, 26 days) and it looks at ALL 26 day periods (from Jan 1/97 to Nov 26/99) and computes the percentage of times you would have made a Gain (over these 26 days) of over 10% or over 20% or less than -5% etc.

Select 250 days and you get (roughly) all one-year returns, ending on ANY day in the period Jan 6/98 to Nov 26/99.
(Uh ... I really should point out that 250 "market" days from Jan 1/97 is Jan 6/98.)

P.S. ATP means All Time Periods, a technique championed by Wilfred Vos.