Rating of scores uploaded to Musescore

Hi, I don't know if any one realises, but I upload quit a bit of the music that I write or rearrange. I have noticed that sometimes these scores are rated. My scores receive both 4 and 5, depending who or how the rating is done. But ALL have at some stage received a 5 star rating. My question is who does the rating and, surely, my songs cannot ALL be 5 stars. Most of my songs seem also to be added to the 'favourites' of your followers.