That 39% means that in under one third of the period (which would be 4 months), I have done over one third of the distance. I am going great! In fact, each month my distance went up, last month I nearly did 100 km.
There is a slight note to this. The total distance last year was calculated using all kilometers I did, whether it was proper walk or not. The total distance this year is calculated using only proper walks. Which means that any steps taken during work are not counted. Any steps taken while going to the shops (unless part of a walk) are not counted. And I still have more km than I did last year.