The Parkinson's Foundation estimates that 930,000 people in the US will have Parkinson's disease.
Currently the Parkinson's Foundation is studying the prevalence of the disease in the United States. The last study that has looked into the prevalence of Parkinson's was in 1978. Their study today, however, indicates that there would be 930,000 people with Parkinson's disease by the year 2020, which is nearly double the amount in 1978. They also estimate that there would be 1.2 million people with Parkinson's disease by the year 2030. The foundation has been observing this trend with their Parkinson's Prevalence Project, which started in 2014.