How many times have you used it?

[strike]

Answer by dividing the times you have made transfers by the months you've owned bitcoins. So example: I've owned bitcoins 21 months and made 110 transactions. 110/21 = 5.2 transfers per month average.

[dstriker]

So if someone used SD that could be a high ratio.  You ought to factor in transaction size.

Months used * (Total coins sent + Total coins Received) / # Transactions


just a thought