Answer is 90 percent.
There are 10 times more bacterial cells in our body than the human cells, according to Carolyn Bohach, a microbiologist at the University of Idaho (U.I.) Although bacterial cells are very large in numbers but these cells take up small space due to smaller than human cells. Babies ingest bacteria during birthing. Babies take up lots of bacteria from their mother's skin and milk—during breast-feeding, the mammary glands become colonized with bacteria. Throughout our lives, we take up bacteria through our food and water.