Hebrews 9:7

but into the second the highpriest alone once every year, not without blood, which he offereth for himself, and for the errors of the people;

Hebrews 9:25

Nor yet to make an offering of himself many times, as the highpriest entereth into the holy place every year with blood of others;

Hebrews 10:3

But in these sacrifices there is a remembrance of sins every year.

Hebrews 10:14

For by one offering he hath perfected for ever those who are sanctified.

Treasury of Scripture Knowledge

Summary

And this shall be an everlasting statute unto you, to make an atonement for the children of Israel for all their sins once a year. And he did as the LORD commanded Moses.

Bible References

Once a year

Hebrews 9:7
but into the second the highpriest alone once every year, not without blood, which he offereth for himself, and for the errors of the people;
Hebrews 10:3
But in these sacrifices there is a remembrance of sins every year.