Hello
You could get that information from the system itself...
By either checking the information form SE13 or querying table DD09L filtering on field TABART = "APPL0".
I'm not sure if the data class from TABART is 100% accurate, as TABART is also used to classify tables at DB level based on their expected size.
You can use the here under SQL query to check the number of tables per dataclass, and the result for an ECC6 Ehp6 system.
Regards
46272 - Implement new data class in technical settings
TXT COUNT(1)
Organization and customizing 48607
Master data, transparent tables 21318
Transaction data, transparent tables 14615
ABAP Dictionary Table 393
Repositoryswitch tablespace 356
SPOOL and logs 289
Source for screens and reports 212
Documentation 117
Customer data class 68
Screen and report loads 43
ODS Tables in BW 9
Facts Table in BW 3
Dimension Tables in BW 1
Set pages 25 lines 256 Col txt for a70 Select substr(tbt, 1, 70) txt, count(1) from (Select dd.TABNAME tbn, t.DARTTEXT tbt from SAPSR3.DARTT t, SAPSR3.DD09L dd where t.TABART = dd.TABART and t.DDLANGU='E') group by substr(tbt, 1, 70) order by 2 desc;