Inflation Rate [USA]

chart_usa_inflation.r

library(dplyr)
library(ggplot2)
library(httr)
library(jsonlite)
library(lubridate)
library(tsibble)

sf <- 2
width <- 600 * sf
height <- 335 * sf

options(vsc.dev.args = list(width = width, height = height, res = 72 * sf))

get_data <- function(from, to) {
  req <- httr::POST("https://api.bls.gov/publicAPI/v2/timeseries/data/",
    httr::add_headers("Content-Type" = "application/json"),
    body = paste0(
      '{"seriesid": ["CUUR0000SA0"], "startyear":"',
      from,
      '", "endyear":"',
      to,
      '"}'
    )
  )
  httr::stop_for_status(req)
  data <- httr::content(req, "text") |>
    jsonlite::fromJSON()

  as_tibble(data$Results$series$data[[1]]) |>
    mutate(year = as.integer(year)) |>
    mutate(period = as.integer(substr(.data$period, 2, 3))) |>
    mutate(value = as.double(.data$value)) |>
    mutate(yearmonth = tsibble::yearmonth(paste0(year, "-", period))) |>
    mutate(value_ref = dplyr::lead(value, 12)) |>
    mutate(value_p = value / .data$value_ref - 1) |>
    filter(!is.na(value_ref)) |>
    select(yearmonth, value_p)
}

current_year <- year(Sys.Date())
#  Load Data
df_inflation <- rbind(
  get_data(current_year - 9, current_year),
  get_data(current_year - 19, current_year - 10),
  get_data(current_year - 29, current_year - 20),
  get_data(current_year - 39, current_year - 30),
  get_data(current_year - 49, current_year - 40),
  get_data(current_year - 59, current_year - 50),
  get_data(current_year - 69, current_year - 60),
  get_data(current_year - 79, current_year - 70),
  get_data(current_year - 89, current_year - 80),
  get_data(current_year - 99, current_year - 90)
)

# Make Chart
chart <- ggplot(
  as_tsibble(df_inflation, index = yearmonth),
  aes(x = yearmonth, y = value_p)
) +
  labs(
    title = "Inflation Rate [USA]",
    subtitle = "Source: bls.gov",
    x = "Month of Year",
    y = "12M Rate of Increase"
  ) +
  geom_line(color = "#5383EC", linewidth = 1.5) +
  geom_hline(yintercept = 0) +
  geom_hline(aes(yintercept = 0.02), color = "#58A65C", linetype = "dashed") +
  scale_y_continuous(labels = scales::percent) +
  ggrepel::geom_label_repel(
    data = head(df_inflation, n = 1) |> mutate(str = paste0(
      yearmonth,
      ": ",
      sprintf("%0.1f%%", value_p * 100)
    )),
    aes(label = str),
    nudge_y = 0.1,
    segment.color = "grey50",
  )

ggplot2::ggsave(
  filename = "chart1.png", plot = chart, width = width, height = height,
  units = "px", dpi = 72 * sf, device = grDevices::png, type = c("cairo")
)