runtime/Lib/site-packages/altair/examples/cumulative_count_chart.py

"""
Cumulative Count Chart
----------------------
This example shows an area chart with cumulative count.
Adapted from https://vega.github.io/vega-lite/examples/area_cumulative_freq.html

"""
# category: area charts

import altair as alt
from vega_datasets import data

source = data.movies.url

alt.Chart(source).transform_window(
    cumulative_count="count()",
    sort=[{"field": "IMDB_Rating"}],
).mark_area().encode(
    x="IMDB_Rating:Q",
    y="cumulative_count:Q"
)