％、。
Fatal cases numbered 19, exceeding 20% of the total, throwing the grim reality of death from overwork into sharp relief.
Literal
Death-cases [subject-が] 19 cases [quotative/and-と] whole [genitive-の] 20% [object-を] exceeding-and [progressive-おり], karoshi [genitive-の] grim reality [subject-が] came-into-sharp-relief.
A news-register sentence. Two notable features: ~ており is the formal/written equivalent of ~ていて (the conjunctive of ~ている), used almost exclusively in writing and formal speech; it chains the progressive/resultative clause into the next. 浮き彫りになる is the idiomatic phrase 'become thrown into sharp relief' — literally 'become a carved relief' — used in reporting and analysis to mean a problem has become starkly visible. 過労死 (karoshi) is the Japanese-coined term for death from overwork, culturally significant enough that it has entered English as a loanword. The と after 19件 is functioning quotatively (specifying the quantity: 'to the tune of 19 cases'), not as a conjunction.