What would be the easiest / most basic form of a hit counter to incorporate into a site? As old fashioned as they are it's been insisted I put one at the bottom of each page - No need for anything flashy just showing the number of visitors is ideal.

I was using one that stored hits in a text file but every so often it will lose the hits, for example it was at 1019 last night and this morning it dropped to 11 - similar happened two weeks ago.