How to: Format Axis Labels as Dates or Currencies
When you show properly formatted DateTime values on an axis, a chart will automatically display these values as days. To specify a date/time interval for the x-axis, such as an interval of months or an interval of hours, you must format the axis labels and set the type of axis interval to a valid date or time interval.
In order to format time intervals correctly, the values displayed on the x-axis must evaluate to a System.DateTime data type. If your field has a data type of System.String, the chart will not calculate intervals as dates or times. For more information, see Preparing Data for Display in a Chart Data Region.
When a numeric value is added to the y-axis, by default, the chart does not format the number before displaying it. If your numeric field is a sales figure, consider formatting the numbers as currencies to increase the readability of the chart.
To format x-axis labels as monthly intervals
Right-click the x-axis of the chart, and select Axis Properties.
In the CategoryAxis Properties dialog box, select Label Format.
From the Category list, select Date. From the Type list, select a date format to apply to the x-axis labels.
Select Axis Options.
In Interval, type 1. In Interval type property, select Months.
If you do not specify an interval type, the chart will calculate intervals in terms of days.
To format y-axis labels using a currency format
Right-click the y-axis of the chart, and select Axis Properties.
In the Value Axis Properties dialog box, select Label Format.
From the Category list, select Currency. From the Type list, select a currency format to apply to the y-axis labels.