A data frame with observations of daily ICU occupancy:
- day: Day of December 2020.
- age_55_and_above: Lower and upper bounds of ICU occupancy for patients aged 55 and above, formatted as "lower-upper".
- age_between_35_and_55: Lower and upper bounds of ICU occupancy for patients aged between 35 and 55, formatted as "lower-upper".
- age_below_35: Lower and upper bounds of ICU occupancy for patients aged below 35, formatted as "lower-upper".
- male: Lower and upper bounds of ICU occupancy for male patients, formatted as "lower-upper".
- female: Lower and upper bounds of ICU occupancy for female patients, formatted as "lower-upper".