Detailed Instructions: Indicate the presence of numerical data in the abstract (whether numerical data plays a key role in medical records), solely using the information from the abstract.
Q: Abstract: Surgical experience with grafts of human dura mater sterilized by gamma rays and preserved in alcohol is reported in 804 cases. The method of graft preparation is a simple, cheap, and practical technique for making available a plentiful quantity of large and small pieces of dura to use for plastic reconstruction in everyday neurosurgical practice. Annual inspection for sterility and immunogenicity over an 18-year period indicates that this system of preservation is valid for an unlimited period of time.
Question: Does the abstract contain any numerical data?
A:
Yes