I am adding flow percentages in my ggalluvial plot based on an existing StackOverflow case (how to calculate percentages in geom_flow() based on variable size and not stratum size) which works fine.

1. It seems that the solution does not define rounded percentages, it just puts percentages in the column based on how much there is room for, so in my case I get one decimal whereas the example has no decimals. I would like to have rounded percentages, but I could not figure out how.

2. Also, it would be nice if I could move the percentages slightly on the x-axis so that the ggrepel lines are not on top of the percentages.

dummy dataset

mult_conc2 <- c("mtx", "mtx", "none", "mtx", "multi", "mtx", "none", "multi")
cond_psoriasis <- c(0, 1, 1, 1, 0, 0, 1, 1)
bio_drug_name <- c("rituximab", "anakinra", "rituximab", "baricitinib", "etanercept", 
"etanercept", "ustekinumab", "guselkumab")
count <- c(50, 50, 40, 70, 30, 25, 25, 70)
allu5 <- data.frame(mult_conc2, cond_psoriasis, bio_drug_name, count, N)
rm("bio_drug_name", "cond_psoriasis", "count", "mult_conc2")
cols <- c("bio_drug_name", "mult_conc2", "cond_psoriasis")
allu5 <- allu5 %>% mutate_at(cols, factor)
rm(cols)

plot

colorfill <- c("tomato4", "tomato3", "tomato2", "tomato1", "tomato", "turquoise", 
 "yellow2", "steelblue1", "springgreen", "snow3", "slategray2", "red1", "purple", "plum1", 
 "olivedrab2")
ggplot(
allu5,
 aes(y = count, axis1 = bio_drug_name, axis2 = mult_conc2)
 ) +
geom_alluvium(aes(fill = bio_drug_name), width = 1 / 12) +
geom_stratum(alpha = 1, width = 1 / 5, fill = "#ffffff", color = "black") +
ggrepel::geom_label_repel(
 stat = "stratum", aes(label = after_stat(stratum)), size = 6,
 direction = "y",
 nudge_x = .25,
 label.size = 0
 ) +
scale_x_discrete(
 limits = c("bio drug name", "concomitant"),
 expand = c(0.1, 0.1)
 ) +
scale_fill_manual(values = colorfill) +
guides(fill = "none") +
ggtitle("b-tsDMARD, concommitant treatment and condition") +
theme(legend.position = "none") +
geom_text(stat = "flow", aes(
 label = scales::percent(after_stat(count)/after_stat(max(ymax))),
 hjust = after_stat(flow) == "to"
 ))