Rule: Last few and next few mean immediately preceding and immediately following, respectively.
Examples of errors:
(1) In the last years everything has become more expensive.
(2) During the last years Christmas presents have become bigger and bigger.
(3) During the last years violence in the form of hijacking has increased.
(4) I'll do it in the next days.
(5) The statement is correct if it refers to the material progress we have achieved during the latest decades.
This misuse of last and next is typical of German speakers translating in den nächsten Tagen, in den letzten Jahren, etc. In English, the omission of few raises the question "Of what?" or "Following what?". Compare:
During the last years of his life he became melancholic
If the more. indefinite meaning of 'recently, immediately preceding' or 'coming, immediately following' is intended, few must be inserted.