Can you look at someone and know when they will die?

I have this eerie ability. I can look at someone or someone's pic and be able to tell when they will die. Not the exact day but within five years. Out of 300 people, I have been right 92 percent of the time. I do it by getting a feeling of how strong their life force is. I gauge how strong it is and come up with a number of years they have left to live.