Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
When 100 g/mi (62 g/km) is the clean electric grid california (san francisco) how many vehicles are there?

### Inputs:
table_name: table, columns: ['Vehicle', 'Operating mode', 'EPA rated All-electric range', 'EPA rated combined fuel economy', 'Clean electric grid California (San Francisco)', 'U.S. national average electric mix', 'Dirty electric grid Rocky Mountains (Denver)']

### Response:
SELECT COUNT Vehicle FROM table WHERE Clean electric grid California (San Francisco) = 100 g/mi (62 g/km)