Spider Solitaire Question

[HeavilyArmed]

I have quit the game as of today after meeting my goal of solving one game. I am curious about estimates from the truly addicted. What percentage of 4 suit games are actually soluable using expert play and no undo? I spent a fair length of time at the 2 suit game and it seemed that maybe 1/3 to 1/5 were soluable but I'm no expert. My guess for the 4 suit game is that it's below 10%. Whadda ya think?