Complete the sentences using present simple passive or past simple passive:

1. In the usa 22 kg of chocolate are ??(eat) every second.

2. Wild tigers ??(not find) in America, but 7000 tigers ??(keep) as a pets in the usa.

3. 1000000usd ??(spend) on pet food every day.

4. The planet Pluto ??(not discover) until 1930.