Here's a screenshot from my Garmin Connect account. These races were all captured with my Garmin Forerunner 10 watch while wearing my Brooks Ghost 9 shoes.
So, when comparing my previous PRs from 2015 and earlier to this year, I have improved my race times by:
1K = 4 seconds
1M = 5 seconds
5K = 1 minute and 23 seconds
10K = 4 minutes and 34 seconds
Half-Marathon = 14 minutes and 49 seconds