Audit regulators have handed BDO USA another scathing inspection report, finding 67 percent of the audits examined in 2016 failed to comply with standards.

The Public Company Accounting Oversight Board selected 24 audits for inspection during its 2016 inspection cycle and found multiple problems in 16 of those audits, or two-thirds. Across the 16 audits, inspectors called out nearly 100 separate violations of auditing standards, including 38 separate instances of failing to comply with Auditing Standard No. 5, which governs the audit of internal control over financial reporting.

Across the eight largest audit firms—minus KPMG, whose 2016 report has not yet been published after allegations of fraud and conspiracy surfaced associated with the inspection process at the firm—BDO’s deficiency rate is the highest by at least 20 percentage points. Big 4 firms Deloitte, EY, and PwC recorded an average deficiency rate of 24 percent, which is the same score earned by Grant Thornton. Crowe landed at 33 percent, and RSM at 47 percent.

The 67 percent rate for BDO is up from a 52 percent rate at the firm in 2015, and that was an improvement over 74 percent in 2014, 65 percent in 2013, and 55 percent in 2012.

In a statement, BDO said it supports the PCAOB’s inspection process. “BDO USA is committed to audit quality and continuous improvement to serve our clients and all of the stakeholders in the capital markets system,” the statement said. “The firm regularly dedicates time and resources to the ongoing enhancement of our quality control programs and the audit services we provide our clients.”

In the audit of an insurance company, “Issuer A” in the report, the PCAOB devotes more than eight pages to describing numerous audit failures, including a total of 15 separate lapses in the internal control audit. The various lapses in the audit of “Issuer B” span the next six pages of the report, where inspectors describe nine separate mistakes with respect to the internal control audit.

The report lists the specific aspects of internal control audits that were most problematic throughout the troubled audits. They included problems with selecting controls to test, testing the design effectiveness of controls, testing the operating effectiveness of controls, and evaluating control deficiencies where they are identified. Other common violations of auditing standards included responding to risks of material misstatements, performing substantive analytical procedures, audit sampling, and evaluating estimates and fair-value measurements.

Although the inspections process called out a high number of audit deficiencies, especially in a few specific audits, inspectors noted that they could not determine from their procedures whether any of the deficiencies were significant enough to allow material misstatements to occur. The report does not indicate that any of the audit failures led to any changes in audit opinions or any issuer restatements.

BDO’s letter contained in the report says the firm took “appropriate action” on the PCAOB findings with respect to the consideration of omitted procedures and the discovery of subsequent facts after the report date, as specified in auditing standards.