使用endpoints / ggplot的中断计算设置ggplot网格线

I have a ggplot issue where I'm trying to make line plots with a very minimal look. I've gotten rid of the legend in favor of text labels at the right side of each line. It might not be so noticeable if the labels weren't so long, but I'd like it better if the gridlines stopped at the maximum x-value (in this case, at the year 2015). issue where I'm trying to make