Approximately what fraction of the human genome encodes proteins?

The Human Genome Project has shown that only a small fraction of our genome actually codes for proteins. About 1% to 2% of our genome consists of exons, which are the coding parts of our genome. The rest of our genome, approximately 98% to 99% of our approximately 3 billion base pairs of DNA, consists of non-coding DNA. Even though some sources give the exact percentage of this part of our genome to be around 1.5%, the commonly used percentage for this part of our genome in academic and biological circles for this topic is around 2%.