[MySQL] Sum of rows

Hi all, hope in your help.

This is my mysql table:

+----+--------+--------+
| id | field1 | field2 |+----+--------+--------+
| 1 | A1 | 7 |
| 2 | B1 | 9 |
| 3 | C1 | 0 |
| 4 | D1 | 3 |
| 5 | A2 | 5 |
| 6 | B2 | 6 |
| 7 | C2 | 7 |
| 8 | D2 | 8 |+----+--------+--------+

I need this output:

+--------+--------------------+
| field1 | field2 |
+--------+--------------------+
| A2 | 19.230769230769200 |
+--------+--------------------+
| B2 | 23,076923076923100 |
+--------+--------------------+
| C2 | 26,923076923076900 |
+--------+--------------------+
| D2 | 30,769230769230800 |
+--------+--------------------+

and tried this query 

where calculate the value of single field1 (5,6,7,8) divided by the sum of field2 equal to A1, B2, C2 and D2 (26) :

A = 5/26 * 100 = 19
B = 6/26 * 100 = 23
C = 7/26 * 100 = 26
D = 8/26 * 100 = 30:

SELECT
field1,
field2/Sum(field2)*100 as field2
FROM
`tbl_t`
WHERE
1
AND field1 IN ('A2', 'B2', 'C2', 'D2');

+--------+--------------------+
| field1 | field2 |
+--------+--------------------+
| A2 | 19.230769230769234 |
+--------+--------------------+
1 row in set

But the ouput is not what I want, can you help me?

Thank you
Any help would be greatly appreciated.