the amendment, the statue only taxed food sales in excess of $1. Thus, the audit in this case involved different audit methods for the periods before and after the amendment’s July 1,1971 effective date. For the audit period prior to the statute’s amendment, petitioner’s food purchase records were examined and found to be in the amount of $283,168.48. This amount was marked up 100% to determine total food sales for the period in the amount of $566,336.96. In order to determine typical sales for the restaurant for a one-week period and to determine the percentage of those sales which exceeded $1 and were subject to the sales tax, the audit division, in the absence of any adequate records maintained by petitioners, chose six tapes representing days during August and September of 1972, which, after examination, revealed that 79.41% of the total sales represented taxable sales of $1 or more. This percentage was then • applied to the estimated amount of pre-July 1, 1971 food sales ($566,336.96) and it was determined that taxable sales amounted to $449,728.18. Petitioners had only reported a taxable percentage of 35% of food sales. For the period July 1, 1971 through February 29, 1972, petitioners’ total food sales, based on a 100% markup of food purchases, amounted to $180,477.28. This entire amount was subject to the sales tax since it represented sales after the $1 exclusion was eliminated. Petitioners, however, had only reported sales for the period in the amount of $135,003, resulting in an “error rate” of 44.35%. For the period March 1, 1972 through February 28, 1974, this error rate of 44.35% was applied to the total taxable sales reported by petitioners ($570,648) to determine additional taxable sales of $253,082.34. Following a hearing respondent modified the audit division’s sales tax assessment after finding (1) that petitioner’s records for the period March 1, 1972 through February 28, 1974 were adequate and that a markup test for that period should not have been used, (2) that employees’ meals constituted salaries and were not subject to sales tax, and (3) that petitioners sold soda in quantities different from those used by the audit division in making its determination. The petition was granted insofar as necessary to correct these errors, but was in all other respects denied. This transferred CPLR article 78 proceeding seeking to challenge respondent’s determination ensued. The record demonstrates unequivocally that petitioners’ records for the period March 1, 1969 through February 29, 1972 were unreliable and incomplete. The only records which were available consisted of hand-recorded entries in a ledger of gross sales figures for each day which were not objectively reliable to satisfy the statutory requirement that records of individual sales be retained for a period of three years (Tax Law, § 1135). Accordingly, it was proper to determine petitioners’ tax liability for this period by resort to other indices, such as purchases (Tax Law, § 1138, subd [a], par [1];
Matter of Urban Liqs. v State Tax Comm., 90 AD2d 576 ;
Matter ofHanratty’s!732 Amsterdam Tavern v New York State Tax Comm., 88 AD2d 1028 , 1029, mot for lv to opp den 57 NY2d 608 ). Next, petitioners’ own expert witness testified that the 100% markup used by the audit division in estimating sales based upon purchases was a conservative figure and petitioners presented no evidence to the contrary. While petitioners’ arguments that the 100% markup figure used was overstated because of inflation and that the audit failed to consider waste and spoilage of food may have some merit, they failed to document their contentions. While exactness in an audit is not required, whatever inexactness existed in the audit was the result of petitioners’ faulty recordkeeping (see
Matter of Korba v New York State Tax Comm., 84 AD2d 655 , 656;
Matter of Markowitz v State Tax Comm., 54 AD2d 1023 , affd 44 NY2d 684 ). Petitioners failed to demonstrate, by clear and convincing evidence, that the amount of tax assessed was erroneous (see
Matter of Urban Liqs. v State Tax Comm., supra). Finally, since the taxing authorities did not fail to comply with any statutory time limits and petition