Considering those authors mentioned more than once in the overall top 20 in each year group, we find they aggregate as follows (see Table 11 in Appendix C).
Jeff Kinney remains the most popular author with an increased number of mentions. David Walliams continues his rise at number two but now has 31 rather than 26 mentions as last year. Roderick Hunt is holding steady at 25, but of course this is all with young children. Roald Dahl maintains his popularity with 23 mentions. Julia Donaldson has risen a little, helped by her new books, while Francesca Simon has declined a little. Zoe Sugg has risen to number seven, helped by her new book. Lower down, Suzanne Collins continues her decline. David McKee, James Dashner and Veronica Roth slip out of the top 20.