I hope this makes sense.

I'm trying to track the ups and downs of two different things. I want to have a chart with two lines on it - A and B and then, on the bottom, I want to show the date.

The problem I'm having is that updates to A and B happen on different dates.

Date      A     B
---------------------------
3-1-08    12  
3-3-08            9  
3-5-08           10
3-8-08    14
3-9-08    15     11
If I put that data into an Excel chart - what happens is that the blanks become '0'. Instead of B showing a smooth line going from 9 to 11 - it's a jagged line that goes 0-9-10-0-11.

Is there anyway to make my chart display what I want? I know I can do the math by hand to fill in the missing data - and I've done that in the past. I end up entering each and every day possible and then figuring the rate of change between real readings; but it's a lot of work and seems wasteful.

Can anyone help me out?