New to the Board..GREAT SITE..Have a question on purchasing Tax Liens

I’m 23 and trying to wedge my foot in the door on the Real Estate game. I’m looking at rolling the dice on some Tax Liens in Northern AZ. I have limited income so this seems to make the most sence in my current situation. My question is…Does anyone know about what percent of tax liens puchased are actually forclosed on? I know the percent would be low if a house with a morgage was on it. As the lender would pay to redeem the property. The liens I’m looking at are raw land (5 Acre parcels) w/ no houses built on them. Has anyone had success on doing this? These will be purchased after the auction (the left overs), so I’ll get 16% on the Liens. In AZ I have to wait 3 years to forclose. Thanks for the help. Any advice on the whole process would be greatly appreciated.