They are claiming that this is the highest graduation rate in the US due to the chart they quote in this press release today: http://tea.texas.gov/About_TEA/News_and_Multimedia/Press_Releases/2015/Texas__high_school_graduation_rate_for_Class_of_2013_again_exceeds_national_average/
The only problem with this claim is obvious when you look at the enrollment by grade patterns over the past decade for Texas:
|Texas Enrollment by Grade 1997-2014|
Click to enlarge image.
When the Cumulative Promotion Index, the last line, is only also 79%, how can you have a graduation rate of 88%. As multiple people are saying, this claim does not match with the data.