motress 0 Newbie Poster

00:24:c3:31:2b:e0 -93
00:12:17:7b:33:04 -80
00:1f:27:55:f7:70 -70
00:1e:13:ee:3e:40 -85
00:24:c3:31:b8:80 -91
00:90:4c:60:04:02 -94
00:1b:0d:d6:6d:50 -70
00:1a:a2:dc:a0:60 -86
00:1e:c1:4c:c5:ce -94
00:24:c3:31:b8:80 -91
00:1e:c1:4c:c5:ce -94
00:1a:a2:dc:a0:60 -91


The above is part of my .txt file, is there any method to calculate the average value for each ID ?
The first part is ID, second is value.
(Note: There are repeated same ID, so how to get those value and calculate average ?

Maybe the result will be :
00:24:c3:31:2b:e0 average : -88
00:12:17:7b:33:04 average : -90
............
..........