Slope of trendline

[Lance Collins <collinsl@xxxxxxxxxxxxxx>]

If I park the cursor on a trendline the popup tells me the slope of the line.

My problem is that I think in % per month and a number like 0.0021 means 
nothing to me.   I could spend a few minutes and work out the relationship 
for myself but I'm lazy and maybe one of you knows the answer offhand?    I 
have spent some time searching the on-line help ( but it doesn't help).

Thanks