The extent of a focal tendon abnormality was intrasubstance in none (0%) of 16 patients with full-thickness tears, one (20%) of five patients with bursal surface partial-thickness tears, two (20%) of 10 patients with articular surface partial-thickness tears, and two (15%) of 13 patients with tendons without tear.
1 Adequate Intake (AI), where no RDA has been established, but the amount established is somewhat less firmly believed to be adequate for everyone in the demographic group.  Tolerable upper intake levels (UL), to caution against excessive intake of nutrients (like vitamin A) that can be harmful in large amounts.
It is why the RDA (Recommended Daily Dietary Allowance) has been revised upwards of ten times since it was created by the National Academy of Sciences in 1941. It was originally created to prevent scurvy (vitamin C deficiency), beriberi (deficiency of thiamine), and pellagra (deficiency of niacin).