Average number of gene products in (a) eukaryote(s)
One answer can be found in the UniProt FAQ:


  What is the human complete proteome?
  
  In 2008, a draft of the complete human proteome was released from
  UniProtKB/Swiss-Prot: the approximately 20,000 putative human
  protein-coding genes were represented by one UniProtKB/Swiss-Prot
  entry, tagged with the keyword 'Complete proteome'. This
  UniProtKB/Swiss-Prot complete H. sapiens proteome (manually reviewed)
  can be considered as complete in the sense that it contains one
  representative (canonical) sequence for each currently known human
  gene. Close to 40% of these 20'000 entries contain manually annotated
  alternative isoforms representing over 15'000 additional sequences ...


http://www.uniprot.org/faq/48

So, we have 20,000 genes and 35,000 products yielding about 1.75 gene products per gene. Alternatively, the 8,000 genes undergoing alternative splicing give about 2.88 proteins per gene.