Вам нужно будет преобразовать данные в совокупную сумму пользователя:
dat <- dat %>% mutate(series1 = cumsum(series1),series2 = cumsum(series2))
fig <- plot_ly(dat, x = ~week, y = ~series2, name = "2019", type = 'scatter', mode = 'lines',
line = list(dash = "dash"))
fig <- fig %>% add_trace(y = ~series1, name = "2020", line = list(dash = "solid"))%>%
layout(
xaxis = list(title = 'week'),
yaxis = list(title = 'Dollars')
)
fig