ipl4
-3
|
not applicable
de
|
| -2
|
don't know/invalid
de
|
| -1
|
Refuse
de
|
| 1
|
Very difficult
de
|
| 2
|
Somewhat difficult
de
|
| 3
|
Neither difficult nor easy
de
|
| 4
|
Somewhat easy
de
|
| 5
|
Very easy
de
|
