You could have easily checked this by running the query
SELECT CURRENT_TIMESTAMP, CURRENT_TIMESTAMP - 5
and comparing the results
"The Transact-SQL timestamp data type is not the same as the timestamp data type defined in the SQL-92 standard. The SQL-92 timestamp data type is equivalent to the Transact-SQL datetime data type"
http://msdn.microsoft.com/en-us/library/aa260631(SQL.80).aspx[
^]
So the answer is days, not ticks