Count Currencies by Market Tier

select market_tier, count(*) as count
from ores.currencies
where valid_to = '9999-12-31 23:59:59'::timestamptz
group by market_tier
order by count desc;

| market_tier | count |
|-------------+-------|
| emerging    |    80 |
| frontier    |    45 |
| g10         |    18 |
| exotic      |    15 |