Git diff --stat explanation

Yes it's the ratio of added and removed lines.

See also:

man diffstat

git diff --numstat "@{1 day ago}"

Parameters:

• diff = Show diff
• --numstat = show the number of lines inserted and removed
• @{1 day ago} = Period.

Output

0   1   WebContent/WEB-INF/tags/Grid.tag38  30  ant/build.xml

• Column 1 (containing 0 38) = inserted
• Column 2 (containing 1 30) = removed

PS: Columns are separated by tab (\t).

As I answered here:

It supposed to reflect the amount of changes (in lines) of each file listed.
Plus signs for additions, minuses for deletions.

The 118 gives the amount of changed lines, and the - / + gives you the proportion of deletions/additions.
When the amount of changes can fit a line you'll get '+' per addition, '-' per deletion;
Otherwise, this is an approximation, e.g.

CHANGES.txt     |   47 +++++++++++++++++++++++++++++++++make-release.py |   77 +++++++++++++++++++++++++++++++++++++++----------------2 files changed, 102 insertions(+), 22 deletions(-)

On CHANGES.txt since you can see that there are no '-', and since 47 '+' are a lot you have a proportionate amount of them (i.e. 100%).
On make-release.py you'll see x39 '+' standing for 55 additions and x16 '-' standing for 22 deletions.
Exactly as their proportion, and just the amount to fit output screen.

The amount of signs per line the a GCD multiple that fits the line width.

Hope that helps.