I believe the speed depends on the weapon your carrying. From what I know Riot Shield is the slowest with 75-80% I think. The LMG's speed would be from 83-90%. Second place would be the assault rifles which is approximately 94-97% and finally the SMG/Pistols/Snipers which I think is from 98-100%. Therefore, adding lightweight to your perks would increase the percentage by 7% I'm guessing. I wouldn't know much about the 'exact' number though those are the statics as percentages. Hope this helped :p
Edit: Threads which are asking for help and/or asking a question belong in the
You must login or register to view this content. section. Please avoid this mistake from happening again as it will keep the forums clean. I will ask a moderator to move this thread to the correct section

Thanks.