"Approximately half of all households in Europe own a pet of some kind. 

The industry supplying these animals and the equipment, feeds and other goods to look after them turns over several 10’s of billion € annually. There are significant health benefits identified for owners keeping pets"-  Reference, European Code of Conduct on Pets and Invasive Alien Species

According to this Code, "keepers can vary from those with a single goldfish, hamster, mouse or other animals in indoor aquaria or cages through to those with thousands of individual animals of species in large outdoor enclosures housing large animals. Some of these enthusiasts specialise in one group, others maintain many groups of animal.

The following observations on the number of species of each group of animals owned as pets throughout Europe, are based on the experience of the authors of the Code:

• Mammals: private keepers hold many hundreds of species in captivity in Europe. The species vary from those owned relatively commonly e.g. hamster, mouse and domestic rat through to giraffe and snow leopard.
• Birds: though the import of wild birds to the EU has been banned it is estimated by the authors that there may be as many as 1,000 species kept. These vary from humming birds to ostriches and include wild fowl collections.
• Reptiles and amphibians: 2,000 species.
• Freshwater fish (Mainly tropical) : 1,000 species.
• Tropical marine fish : 1,000 species.
• Aquatic invertebrates: (hard corals, soft corals, crustacean and molluscs): 1,000 species.
• Terrestrial invertebrates: at least 500 (including scorpions, whip scorpions and solifugids but also including beetles, stick insects, praying mantis, land crabs, land snails and at least 200 spider species).
  
• Thus almost 7,000 species may already be owned, some for a considerable period, by households as pets in Europe".