That tells you who has a certification for it. Note must people have certifications for multiple RNGs, including openssl (indeed a few of those modules are wrappers around openssl)
There is one company that only has a cert for EC_DRBG and thus can reasonably be inferred to be using it is Lancope, a network security/firewall company. For the rest of them, we don't know.
McAfee Firewall Enterprise Control Center only has dual EC_DRBG certified (despite the fact the RSA library they use supports others; strongly suggesting its what they actually use).
There is one company that only has a cert for EC_DRBG and thus can reasonably be inferred to be using it is Lancope, a network security/firewall company. For the rest of them, we don't know.