Do you really want just 3 columns? Presumably you are importing this
to Excel so you can perform statistical analysis on the results,
perhaps a frequency count to determine the most commonly occurring
numbers. If that's the case you'll need the numbers in their
individual cells.

For just three columns, try this: copy the data on the website into the
clipboard, open a blank spreadsheet, and paste into cell A1. Highlight
Column A and from the menu click Data Text to Columns, choose the
Delimited radio button, and click Next. In the next window's Delimiters
box, select Other and enter a - in the box, then click the Treat
Consecutive Delimiters as One checkbox. Click Finish, and the three
columns appear. You can clean up that leading comma in column B by
inserting a new column immediately to the right of column B and
entering this formula in C1:
=MID(TRIM(B1),2,LEN(TRIM(B1))-2)
....then copy and paste that down for remaining dates.

If you would like to have each number in its own cell for statistical
analysis, follow the same process as above, but select the Comma
checkbox for your delimiter.