GSTR 9 for the FY 17-18

I file gstr 3b monthly and gstr1 quertly and claim IatC and also paid extra tax monthly in gstr3b. but I try to file gstr9. when I start to file the. one question regarding filing of nil return or not. what can I do. kindly quid me for filing gstr9 return. my annual sale for the financial year 17-18 is 374739 and tax payable 68074.