Book progress

Just noticed an interesting thing. I read (on average) about 35% of the book, then I leave it and pick something else to read.

 

I am currently reading 4 books.

1. 25% done

2. 35% done

3. 40% done

4. 55% done

 

They are not bad books and not boring either. What is going on? O.o

Mammarella

Currently reading

Brethren
W.A. Hoffman
Progress: 3 %
The Virtu
Sarah Monette
Progress: 30 %
Orochi no Kishi
Itoshi, Lehanan Aida
Progress: 80 %