What are the percent chances of infecting a baby with HIV through breastfeeding.?

Enough. While low if you are well treated with a low viral road, it is still present.The American Academy of Pediatrics advises against breastfeeding in the US.
Good. If you have hiv, are untreated and have a high viral load, the chances of transmission are present. Percentages are only good for populations and scientific studies, because getting a potentially fatal disease is 100% for those who get it. Listen to your doctor.