Give the country id and corresponding count of cities in each country.
SELECT country_id, COUNT(*) FROM locations GROUP BY country_id
``` yaml
locations: # name of dataframe
- LOCATION_ID:
    dtype: int64
    sample_values: 1000, 1100, 1200
- STREET_ADDRESS:
    dtype: string
    sample_values: 1297 Via Cola di Rie, 93091 Calle della Testa, 2017 Shinjuku-ku
- POSTAL_CODE:
    dtype: numeric
    sample_values: 989, 10934, 1689
- CITY:
    dtype: string
    sample_values: Roma, Venice, Tokyo
- STATE_PROVINCE:
    dtype: string
    sample_values: ', , Tokyo Prefecture'
- COUNTRY_ID:
    dtype: string
    sample_values: IT, IT, JP

```
COUNTRY_ID,COUNT(*)
"""",1
AU,1
BR,1
CA,2
CH,2
CN,1
DE,1
IN,1
IT,2
JP,2
NL,1
Ox,1
SG,1
UK,2
US,4
