The process of DNA replication occurs just before S phase. In the interphase, the cell has growth and replication of DNA is getting made. In the G1 phase, there is the growth, (G1-checkpoint - cell size, growth, environment shows cell is ready to start replicating DNA. S phase- DNA is replicated.
I think the answer is 90%. According to the recent National institute of Health, Microbes in the human body estimates that 90% of the cells in human body are bacterial, fungal, or otherwise non-human. Despite the arguments that bacteria enjoys a commensal relationship with the humans hosts, only a fraction of the human microbia has been characterized.