awk - delete last two letters

Shell Programming and Scripting
1

Hello!

How do I remove the last two letters "GB" off each line, using awk?
What I need to remove is the "GB" in following input:
.....
30GB
2504GB
3GB
40GB
......

The OS used is Solaris9

Regards,
Fredrik

2 
echo '30GB' | nawk 'sub("..$", "")'