To open SQLite Things.app database run this command in Terminal.app:
$ sqlite3 ~/Library/Containers/com.culturedcode.things/Data/Library/Application\ Support/Cultured\ Code/Things/ThingsLibrary.db
In SQLite command-line type this query to get your tasks stats:
sqlite> .mode column
sqlite> .header on
sqlite> select zscheduler, zstatus, ztrashed, count(*) from ZTHING where z_ent = 13 group by zstatus,ztrashed order by Z_pk desc;
ZSCHEDULER ZSTATUS ZTRASHED count(*)