Since the INGE was formed in 1999, the group has expanded somewhat and now includes R&D and operational groups from many locations around the world. Although there is no official list of INGE members, the group is informally composed of scientists, engineers, and others from Argentina, Austria, Australia, Canada, China, France, Germany, Japan, Norway, South Korea, Sweden, Russia, the United States, and several other countries. These members regularly contribute to better understanding radioactive xenon measurements through operation of samplers, measurements of background at various locations, creation of data analysis routines, etc.