id     date       employee_type  employee_level
1   10/01/2015        other            2
1   09/13/2011      full-time          1
1   09/25/2010       intern            1
2   09/25/2013      full-time          3
2   09/25/2011      full-time          2
2   09/25/2008      full-time          1
3   09/23/2015      full-time          5
3   09/23/2013      full-time          4

id     date       employee_type  employee_level
1   10/01/2015        other            2
1   09/13/2011      full-time          1
1   09/25/2010       intern            1