The following is the Nov. 19, 2018 Government Accountability Office report, Navy Readiness: Actions Needed to Address Costly Maintenance Delays Facing the Attack Submarine Fleet.
From the report:
The Navy has been unable to begin or complete the vast majority of its attack submarine maintenance periods on time resulting in significant maintenance delays and operating and support cost expenditures. GAO’s analysis of Navy maintenance data shows that between fiscal year 2008 and 2018, attack...
https://news.usni.org/2018/11/19/gao-report-u-s-attack-submarine-maintenance-backlog