SELECT EXTRACT(YEAR
FROM CAST(invoice_date AS date)) ,
MIN(total),
MAX(total),
SUM(total),
COUNT(*),
--ROUND(SUM(total)/COUNT(total))
ROUND(SUM(total)/COUNT(customer_id))

FROM invoice
WHERE billing_country IN ('USA',
'United Kingdom',
'Germany')
GROUP BY EXTRACT(YEAR FROM CAST(invoice_date AS date))
ORDER BY EXTRACT(YEAR FROM CAST(invoice_date AS date)) DESC;