As announced previously, we have reviewed our global portfolio of institutions with the goals of simplifying and focusing our operations, reducing complexity, mitigating risks (such as political, regulatory, economic and currency), exiting smaller markets where our operations have less scale and maximizing our exposure to what we believe are the most attractive and scalable markets for our network. We have undertaken a series of divestitures calculated to simplify and streamline our business. In 2017, we announced the divestiture of certain subsidiaries in our then-existing Europe, Middle East, Africa and Asia Pacific ("EMEAA") and Central America & U.S. Campuses segments. On August 9, 2018, we announced that we plan to divest additional subsidiaries located in Europe, Asia and Central America, which were included in the then-existing EMEAA, Andean & Iberian, and Central America & U.S. Campuses segments. As of September 30, 2018, we refer to the EMEAA segment as our "Rest of World" segment and to the Andean & Iberian segment as our "Andean" segment. We have decided to focus principally on the Latin American markets where we operate large-scale platforms, as well as on the online market in the United States.
We are the largest international network of degree-granting higher education institutions, primarily focused in Latin America, with approximately 875,000 students enrolled at over 25 institutions with more than 150 campuses, which we collectively refer to as the Laureate International Universities network. The institutions in the Laureate International Universities network are leading brands in their respective markets and offer a broad range of undergraduate and graduate degrees through campus-based, online and hybrid programs. As of December 31, 2018, approximately 93% of our students attend traditional, campus-based institutions offering multi-year degrees, similar to leading private and public higher education institutions in developed markets such as the United States and Europe. Nearly two thirds of our students are enrolled in programs of four or more years in duration.
Our programs are designed with a distinct emphasis on applied, professional-oriented content for growing career fields and are focused on academic disciplines that we believe offer strong employment opportunities and high earnings potential for our students. We continually and proactively adapt our curriculum to the needs of the market. In particular, we emphasize science, technology, engineering and math (STEM) and business disciplines, areas in which we believe that there is large and growing demand, especially in developing countries. Since 2009, we have more than doubled our enrollment of students pursuing degrees in Medicine & Health Sciences, Engineering & Information Technology and Business & Management, our three largest disciplines. We believe the work of our graduates in these disciplines creates a positive impact on the communities we serve and strengthens our institutions' reputations within their respective markets. Our focus on private-pay and our track record for delivering high-quality outcomes to our students, while stressing affordability and accessibility, has been a key reason for our long record of success.