stats: some grammar layout and content additions/adaptions

note that much less changed that it seems from a line-based git use
git show --word-diff=color --word-diff-regex='\w+' to see actual
change.

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

pmg-statistic.adoc

@@ -1,13 +1,13 @@
 Statistics
 ==========
 
-{pmg} offers a useful and feature-rich statistics interface, which allows the
+{pmg} provides a useful and feature-rich statistics interface that allows
-administrators to quickly see the general workload and makes it easy to identify
+administrators to quickly get an overview of the overall workload and easily
-problems.
+identify problems.
 
-The statistics are shown for the selected time range, which defaults to the
+The statistics are displayed for a selected period, which by default is the
-current day, but can be changed to any other day, a whole month, or even a
+current day. This period can be changed to any other day, a whole month or even
-whole year.
+a whole year.
 
 On the main statistics page there are three graphs with additional data:
 
@@ -23,8 +23,8 @@ Shows the total mail flow as a graph and the following details:
 
 'Incoming Mails'::
 
-Shows the incoming mail counts as a graph and the following details
+Displays the count of incoming mails from each of the following categories,
-(as counts and percentages of the incoming mail volume):
+including their percentage of the total incoming mail volume:
 
 * Incoming Mails
 * Junk Mails (Virus + Spam + Greylisted + SPF rejects + RBL rejects)
@@ -36,8 +36,8 @@ Shows the incoming mail counts as a graph and the following details
 
 'Outgoing Mails'::
 
-Shows the outgoing mail counts as a graph and the following details
+Displays the count of outgoing mails from each of the following categories,
-(as counts and percentages of the outgoing mail volume):
+including their percentage of the total outgoing mail volume:
 
 * Outgoing Mails
 * Bounces (mails with an empty envelope-sender address)
@@ -46,20 +46,22 @@ Shows the outgoing mail counts as a graph and the following details
 Spam Scores
 -----------
 
-This panel shows the distribution of the different spam scores for the selected
+The `Spam Scores` panel shows the distribution of the different spam scores for
-time frame.
+the selected time period. Note that you can also select a whole month or even a
+whole year as period to display.
 
 Virus Charts
 ------------
 
-This panel shows which and how many viruses were detected in the selected
+The `Virus Charts` panel shows which and how many viruses were detected in the
-time frame.
+selected time period.
 
 Hourly Distribution
 -------------------
 
-Shows the amount of incoming and outgoing mail per hour for the selected
+The `Hourly Distribution` shows the amount of incoming and outgoing mail per
-time frame.
+hour for the selected time period. For periods spanning a whole month or a
+whole year the arithmetic average of mail volume in an hour will be shown.
 
 Postscreen
 ----------
@@ -71,16 +73,17 @@ https://www.postfix.org/POSTSCREEN_README.html[postscreen readme].
 Domain
 ------
 
-Contains a summary for the recipient domain of the incoming and outgoing mails
+The `Domain` view is split into two tabs, one for incoming and one for outgoing
-of the selected time frame, with traffic, count, how many viruses were detected,
+mails. Each shows a summary grouped by the recipient domain in a selected time
-and how much of it was spam.
+frame, with stats for traffic, count, how many viruses were detected, and how
+much of the mail volume was classified as spam.
 
 Sender
 ------
 
-This panel contains a list of e-mail addresses that sent mail out in the
+The `Sender` panel contains a list of e-mail addresses that sent mail out in
-selected time frame, with a total count, how many viruses were detected and how
+the selected time frame, with a total count, how many viruses were detected and
-big these mails were.
+how big these mails were.
 
 If you click on one of these e-mail addresses, you see a detailed list of
 recipients, complete with size, date and time.
@@ -95,9 +98,9 @@ as the total mail size.
 If you click an entry, it shows a detailed list of mails with size, date,
 time, virus and spam score info.
 
-If the `advanced statistics filters` are active, only active accounts will be
+If the `Use advanced statistics filters` option (`Configurations -> Options`)
-listed. Active accounts are those which sent mail in the selected time frame
+is enabled, only active accounts will be listed. Active accounts are those that
-or up to 90 days before.
+sent mail during the selected time period or up to 90 days before.
 
 Contact
 -------
@@ -107,7 +110,7 @@ This contains the list of external recipients that received mail from this
 
 If you click an entry, it shows a list of mails with size, date and time.
 
-If the `advanced statistics filters` are active, active accounts will be
+If the `Use advanced statistics filters` option (`Configurations -> Options`)
-filtered out, since they can already be seen in the `Receiver` panel. Active
+is enabled, active accounts will be filtered out, since they can already be
-accounts are those which sent mail in the selected time frame or up to 90 days
+seen in the `Receiver` panel.  Active accounts are those which sent mail in the
-before.
+selected time frame or up to 90 days before.