No there is no Percentage Restriction in Civil service examination.. you just pass gruation level degree course ,..civil Service examination organized by Union public service commission below :

Educational Qualification
You have to pass any undergraduate Degree from any well Recognized University or equivalent.

Age - limits:
21-30 years as on 1st August of the year of Examination.

Fee :
All Female candidates SC/ST/PH Candidates are exempted from the payment of fee.
General category fee : Rs. 100/- (Rupees One Hundred only)

Scheme of CS (Preliminary) Examination
The Preliminary Examination consists of two papers of objective type (multiple-choice questions) carrying a maximum of 400 marks.
General Studies Paper - I 200 Marks
General Studies Paper - II 200 Marks

Scheme - CS (Main)

Paper-I
One of the Indian Languages to be selected by the candidate from the 18 languages included in the VIIIth Schedule to the Constitution (Qualifying Paper) 300 Marks
Paper-II English (Qualifying Paper) 300 Marks
Paper-III Essay 200 Marks
Papers IV & V General Studies (300 Marks for each paper) 600 Marks
Papers VI, VII, VIII & IX
Any two subjects (each having 2 papers) to be selected from the prescribed optional subjects (300 marks for each paper) 1200 Marks
Total Marks for Written Examination 2000 Marks
Interview Test 300 Marks
Grand Total 2300 Marks

Important Dates
Starting Date of Registration: 31st May 2014
Last Date for Receipt of Applications: 30th June 2014, till 11.59 p.m.
Date of Examination: 24th August 2014