# packages
library(tidyverse)

# read pmms data
df <- read_csv("PMMS_history.csv")

# make date into date format
df <- df %>%
  mutate(date = as.Date(date, format = "%m/%d/%Y"))

# arrange data in tidy format
df <- df %>%
  select(date, pmms30, pmms15, pmms51) %>%
  rename("30-Yr FRM" = 2, "15-Yr FRM" = 3, "5/1 ARM" = 4) %>%
  pivot_longer(-date, names_to = "rate_type", values_to = "rate_value")
 
# generate line plot for rates
df %>%
  ggplot(aes(x = date, y = rate_value/100, color = rate_type)) +
  geom_line() +
  scale_x_date(date_labels = "%Y", date_breaks = "8 years") +
  scale_y_continuous(labels = scales::percent) +
  labs(title = "Primary Mortgage Market Survey (PMMS)",
       subtitle = "U.S. Weekly Averages since April 1971",
       caption = "Source: Freddie Mac",
       x = "", y = "", color = "") +
  theme_bw() +
  theme(text = element_text(family = "serif"),
        plot.title = element_text(hjust = 0.5),
        plot.subtitle = element_text(hjust = 0.5),
        legend.position = c(.88,.93),
        legend.background=element_blank())