การเพิ่มข้อความพื้นหลัง

# Add the year as background text and remove the slider
us_economy %>%
  plot_ly(x = ~gdp, y = ~house_price, hoverinfo = "text", text = ~state) %>%
  add_text(x = ___, y = ___, text = ___, frame = ___,
           textfont = list(color = ___(___), size = ___)) %>%
  add_markers(size = ~population, color = ~region, 
              frame = ~year, ids = ~state,
              marker = list(sizemode = "diameter", sizeref = 3)) %>%
  layout(xaxis = list(title = "Real GDP (millions USD)", type = "log"),
         yaxis = list(title = "Housing price index")) %>%
  ___(___ = ___)