[Conky] Bad Substitution

Greetings, I'm attempting to use Conky to overlay information about my hardware. I've managed to modify the default Conky config to my liking, however there's one line that's giving me an error ( bad substitution ). The command works perfectly in terminal but not with Conky.

This is the line of code. I'm attempting to make a bar which is filled based on GPU load. The error is produced when I attempt to pipe the 'grep' output to 'awk' which is supposed to remove the percent sign from the string ( execbar does not seem to like percent signs ).

${execbar ${exec aticonfig --adapter=0 --od-getclocks | grep -i -o [0-9]% | awk 'sub(/%/, "")' } }

runedog48@ThomasTheTrain /etc/conky $ aticonfig --adapter=0 --od-getclocks | grep -i -o [0-9]%
0%
runedog48@ThomasTheTrain /etc/conky $ aticonfig --adapter=0 --od-getclocks | grep -i -o [0-9]% | awk 'sub(/%/, "")' 
0

Any help would be greatly appreciated.