History icons "week" and "month" are gone in Internet Explorer 9?

I think I may have accidentally deleted the icons "Week" and "Month. I can view "Today" in history, but cannot view "Week" or "Month", they are gone. Under internet options, browsing history settings, it is set to keep browsing history for 20 days and 250mb disk space to use. The "delete history on exit" box is unchecked. Is there any way to get the icons back so I can view history for more than a day?