SQL Server Reporting Services x-axis interval

Question

I have a chart in SSRS that needs to have a flexible x-axis grid line interval (show at most 6 major grid lines), and I'm using the formula I've used dozens of times before:

=Floor(Count(Fields!Date.Value)/5)

However, for some strange reason, the chart only ends up showing the first value on the x-axis. The line gets plotted correctly, but there are no grid lines and no x-axis labels save the first one.

What's going on?

Answer 1

Well I found the answer. The data set I'm using has multiple fields, some of which are not being used by the chart. However, because the column I'm grouping on may have several repeat values, I had to change Count() to CountDistinct(). This resolved the issue.