SSRS : Display default value in report parameter?

The datasource for my Hour parameter in my SSRS report is the following query:

SELECT HOUR
FROM  [HourlyData]
GROUP BY HOUR
order by hour desc

When I run the report, I need to select an hour before running the report. Is it possible that the parameter dropdown displays by default the most recent hour? That way, if a user clicks on the report, data will automatically be displayed.

Thanks.

VM