This is quite a high number. It seems to be something like 20 % of all queries!
Compare this to my Pi-hole
$ sqlite3 /etc/pihole/pihole-FTL.db --header --column "SELECT status, count(*) "absolute", printf('%.2f%%',(100.0*count(*)/(SELECT count (*) FROM queries WHERE timestamp > strftime('%s','now','-24 hours')))) "relative" FROM queries WHERE timestamp > strftime('%s','now','-24 hours') group by status order by status asc;"
status absolute relative
---------- ---------- ----------
1 1527 11.12%
2 5616 40.89%
3 6487 47.23%
9 7 0.05%
12 20 0.15%
14 77 0.56%
where the in-progress queries are only some 0.6%.
If you have the time, it'd be interesting if you could check one or two of them, compare what pihole.log says* and if that matches the database. It should, but checking can never hurt.
*) I know it doesn't say much but you could check if the query came in multiple times but was forwarded only once. Also, pihole-FTL.log may contain something usefull if you still have query debugging enabled.