Why different all-strings counts between languages?

Currently, from http://translate.userecho.com , when you enter one language area, you can notice that the whole number of available strings ("All" column, whatever they are translated or not) is not the same in every languages.

For instance today for Admin Interface, Chat, Mobile, Userecho, User:

English = 610, 110, 48, 401, 1214

French = 610, 110, 48, 30, 1118

Russian = 610, 110, 48, 401, 1214

Ukrainian = 610, 110, 48, 30, 1118

Why is there less available strings to be translated in certain languages?

That's strange for a translator...