statement to find at least a year with register users > 1
You need to GROUP BY year, and use a HAVING clause to further limit only the grups where the count or rows (count(*)) is greater than 1:

SELECT
    year
FROM
    users
GROUP BY
    year
HAVING
    count(*) &gt; 1
ORDER BY
    year ;


You get:

| year |
|------|
| 2016 |


You can check it at SQLFiddle