Here’s a version of the argument with effective transitions to enhance its flow and coherence:
"Year-round school has seen an increase in districts nationwide. Studies show, for instance , that more than 10 percent of students are now enrolled in year-round schools, an increase of 544 percent over the last 27 years. Furthermore , so many new districts are joining the year-round schedule that it is now considered a trend. Therefore , schools should consider switching to the year-round schedule to keep up with the latest educational reforms."