In Bereshit 46 the Torah tells us that there were 70 descendents of Jacob who came to Egypt with him (excluding the wifes)
33 descendants through Leah 16 through Zilpa 14 throgh Rahel 7 through Bilah
All together 70 descendants.
Then the Torah says there where 66 people (again excluding the wifes) coming with Jacob to Egypt and Joseph and his two sons were already in Egypt.
Means: 69 People.
This makes Rashi comment that Yocheved was born on the way to Egypt.
My question is: If Yocheved is one of the 70, which one of the already mentioned 70 people was eradicated from the list ?