The gearing factor which is shown in the table, is just the amount of source line codes in a language that, in average, correspond to one function point.
These projects are from QSM's data, and will vary much from organization to organization and even team to team. QSM note this on the page as well.
Even if the data was 100% correct and applicable in all environments, it still doesn't show you which language has the lowest effort. It really only indicates how verbose the syntax is for each language.
For example PowerBuilder takes in average only 26 lines, whereas J2EE is 46 and C# is 54. This would indicate Powerbuilder to be much more efficient. In reality, Powerbuilder is a 4gl language which indeed is very efficient, but only for a pretty narrow type of application (CRUD desktop client/server apps). Writing a modern web-app in Powerbuilder however, would take orders of magnitude more effort than writing it in C#.
So this table is certainly nothing that should factor into a choice of technology. A much better factor in choosing tech, is as simple as whatever your team is more experienced in.