This study emerged from a multi-institutional and interdisciplinary partnership. The maps, affiliated statistics and data sets represent the tangible products of numerous conceptual and technical discussions held over the span of several years plus earlier work that set the foundation for the current analysis. We recognize that questions and comments may arise from both scientists and the general public alike. We welcome your inquiries, which can be directed to our general email address at firstname.lastname@example.org. Someone will respond to your correspondence as quickly as possible. Thank you for your interest in our work.