Avg() Is Not Including 0's

Hi,

I have a sql query like this

select avg([mycolumn]) from data where date > '1/5/08' and date < '1/10/08'
group by [mycolumn]
order by [mycolumn] desc

If all values within that average are numbers, I'm fine. If it's a 0 (not a null, a 0) it doesn't get averaged in. For instance, values 0,1,2 should produce an average of 1.

(0+1+2)/3 = 1.

But sql is returning a value as if my 0's were nulls and not factored in:

(1+2)/2 = 1.5

Does anyone know why this is happening and how to fix it?