I'm reading this article about a peace ceremony held in Nagasaki.
There is a sentence that uses a と, but I do not understand the meaning entirely. I believe the と is being used as an "and" but I don't know why or how. I have only seen と used as an "and" when its is between two nouns like
猫と犬
Cat and dog
If I am correct is it because the と is between two relative clauses?
Sentence: 去年からの1年に亡くなった人と亡くなっていたことがわかった人は3511人です。
My Translation: Since last year, people that have died in the year and people who understood the event that were dying are 3511.