In 2000, ten million people volunteered to support the immunization of 550 million children as part of the Global Polio Eradication Initiative. The vast majority were concerned citizens, volunteering in their own communities. They gave their time to ensure that children reported to immunization stations, were properly documented, and received the oral vaccine. The total value of their support was estimated at US $10 billion – a contribution well beyond the reach of governments or international and national organizations.