Erratic Chart Generated from Data

Hello

I'm using 2010. I want to generate a chart with two series (sets of data points) showing dollar amount on the left y-axis and a number of units on the right y-axis and month dates (such as 7/14) on the x-axis.

Please see the attached screenshot showing the resulting chart and part of the data. The data range is shown in Column B from 2/10 (Feb. 2010) to 4/14 (too big for the screenshot). The number of units is in Column C, and dollar amounts in Column D. There are three months that have missing data (two shown on the screen).

As you can see the chart turned out quite erratic. The range is not complete, the series 2 line (dollar amount) has a weird vertical component for each month, and I don't know how to get a second y-axis on the chart for the blue line (number of units).

Any help you can offer will be most appreciated.

Thanks.

Pete291