How Can the Technology Relevance Have a Positive Value if the Market Coverage is “0”?

While a patent family might no longer be protected in any authority and therefore have a Market Coverage and Competitive Impact of "0", it still may be significant for subsequent art, as expressed in the citations it still receives or has received from other patent families. Therefore, the Technology Relevance is calculated for both active and inactive patent families even after the expiry of a patent family.