In 2001 Cisco shed 13,000 of 48,000 employees and contractors which was 27%. Cisco has been laying off in both small and big batches, sometimes as often as quarterly, for almost 23 years. Saying there will be more is like saying the ocean will continue to be wet.
Few of you seem to know/remember when part of this was done using Jack Welch's "vitality curve" (aka "rank and yank".) Annually GE fired the bottom 10% while Cisco fired the bottom 5%. As we've seen many times with Cisco they hire at a rate to make up the loss and more fairly quickly. On top of that hiring Cisco will add what, another 7,000 employees with Splunk?
The infinitely more important issue is how much of Cisco's staff needs to change to both fix the vast majority of the technical debt once and for all, then acquire the business, engineering and management skills to do development in whole new areas. While I don't have a specific number I'm positive 5%/year won't get you there.