Who Comes First, Aunts or Uncles?

When I was growing up when we referred to aunts and uncles, sometimes we named the aunt first, but sometimes it was the uncle. Why was that?

From my parents' siblings we had these at family gatherings:

Aunt Vida and Uncle Fred (Johnson)

Aunt Buena and Uncle Walt (Severy)

Uncle Jerry and Aunt Ruth (Falk)

Aunt Violet and Uncle Mel (Moorehead)

Aunt Erma and Uncle Adolph (Grinde

From my grandparents' siblings we talked about:

Uncle Arthur and Aunt Della (Albertson)

Uncle Ernest and Aunt Ollie (Albertson)

Aunt Lake and Uncle Joe (Elliott)

Aunt Celia and Uncle Clarence (Pettibone)

Uncle Marvin and Aunt Evelyn (Smalley)

Aunt Julia and Uncle Roy (Everett)

Uncle Spike and Aunt Ruby (Smalley)

Uncle Roy and Aunt Grace (Bond)

In all these cases it was the sibling of parents and grandparents who was named first. I wonder if this is the same in other families.