New evidence suggests that the overall similarity between
human and chimp DNA is between 70-81 percent.
For example, The Era of Chimp to Man is Over tells us that:
"Given the fact that the chimpanzee genome is at least
10 percent larger overall than the human genome ..."
the 98% assertion is simply inaccurate.
See Here and the Links below for more details
Journal Reports Bias in Human-Chimp studies
Does ... DNA similarity ... prove common ancestry?
Human-Chimp Genetic Similarity: Is Evolutionary Dogma Valid?
Common DNA Sequences: Evidence of Evolution or Efficient Design?
See also Here and scroll down to:
Greater than 98% ... similarity? Not any more