diff --git a/stats.js b/stats.js
index 02fc6b4..095e103 100644
--- a/stats.js
+++ b/stats.js
@@ -29,6 +29,16 @@ var getBytes = function(s) {
     return bytes;
 };
 
+var getDatetime = function (number, units) {
+    var datetime = moment();
+    if (number) {
+        return datetime.subtract(number, units);
+    } 
+    // round to whole minutes
+    return datetime.format('YYYY-MM-DD HH:mm:00');
+};
+
+
 var getContainers = function() {
     var containers = {};
     var out;
@@ -86,16 +96,31 @@ var getCreateContainerId = function(name, cid, cb) {
 };
 
 var writeContainerStats = function(cid, container, now) {
-    getCreateContainerId(container.name, cid, function(id) {
-        var stm = db.prepare("INSERT INTO stats (id, ts, cpu, mem, net_in, net_out, block_in, block_out) " +
-            "VALUES (?, ?, ?, ?, ?, ?, ?, ?)");
-        stm.run(id, now, container.cpu, container.mem, container.net.in, container.net.out, container.block.in, container.block.out);
-        stm.finalize();
+    getCreateContainerId(container.name, cid, function (id) {
+        // get the last stats
+        db.get('SELECT net_in, net_out, block_in, block_out FROM stats WHERE id = ? ORDER BY ts DESC LIMIT 1', id, function (err, row) {
+            if (err) {
+                console.error(err);
+            }     
+
+            if (row) {
+                // make values relative
+                if (container.net.in > 0)       container.net.in    -= row.net_in;
+                if (container.net.out > 0)      container.net.out   -= row.net_out;
+                if (container.block.in > 0)     container.block.in  -= row.block_in;
+                if (container.block.out > 0)    container.block.out -= row.block_out;
+            }
+
+            var stm = db.prepare("INSERT INTO stats (id, ts, cpu, mem, net_in, net_out, block_in, block_out) " +
+                "VALUES (?, ?, ?, ?, ?, ?, ?, ?)");
+            stm.run(id, now, container.cpu, container.mem, container.net.in, container.net.out, container.block.in, container.block.out);
+            stm.finalize();
+        });
     });
 };
 
 var writeStats = function(containers) {
-    var now = moment().format('YYYY-MM-DD HH:mm:ss');
+    var now = getDatetime();
     for (var id in containers) {
         var container = containers[id];
         writeContainerStats(id, container, now);
@@ -110,6 +135,7 @@ var main = function() {
 };
 
 var cleanupContainers = function (activeContainers) {
+
     // get list of active containers
     var list = [];
     for (var key in activeContainers) {
@@ -125,33 +151,38 @@ var cleanupContainers = function (activeContainers) {
     // ids
     var ids = list.join(',');
 
-    // delete all non-active containers
-    var sql = `DELETE FROM containers WHERE name NOT IN (${ids})`;
-    db.all(sql, function (err, rows) {
-        handleError(err);
-        // delete stats on these containers
-        db.all('DELETE FROM stats WHERE ID NOT in (SELECT id FROM containers)', function (err, rows) {
-            handleError(err);
-            // cleanup old stats
-            var old = moment().subtract(CLEANUP_DAYS, 'days').format('YYYY-MM-DD HH:mm:ss');
-            db.all('DELETE FROM stats WHERE ts < ?', old, function (err, result) {
-                handleError(err);
-            });
-        });
-    });
-};
+    // vars
+    var cleanupDays = moment().subtract(CLEANUP_DAYS, 'days').format();
+    var CleanupWeekly = moment().sub
 
-var handleError = function (error) {
-    if (error) {
-        console.error(error);
+    // cleanup queries
+    var cleanupQueries = [
+        `DELETE FROM containers WHERE name NOT IN (${ids})`,
+        'DELETE FROM stats WHERE ID NOT in (SELECT id FROM containers)',
+        `DELETE FROM stats WHERE ts < '${getDatetime(CLEANUP_DAYS, 'days')}'`,
+        `DELETE FROM stats WHERE ts < '${getDatetime(1, 'day')}' and strftime('%M', ts) != '00'`,   // keep hourly records after one day
+        `DELETE FROM stats WHERE ts < '${getDatetime(1, 'week')}' and strftime('%H', ts) != '00'`,  // keep daily records after one week
+        `DELETE FROM stats WHERE ts < '${getDatetime(1, 'year')}' and strftime('%d', ts) != '00'`,  // keep daily records after one month
+    ];
+
+    for (var query of cleanupQueries) {
+        db.all(query, function (err, rows) {
+            if (err) {
+                console.error(err);
+            }
+        });
     }
 };
-
 db.run("PRAGMA journal_mode=WAL");
 
+// create tables
 db.run("CREATE TABLE IF NOT EXISTS containers ( " +
     "id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, " +
-    "name TEXT NOT NULL)");
+    "name TEXT NOT NULL)",
+    function (err, result) {
+        db.run("CREATE INDEX IF NOT EXISTS containers_name ON containers(name)");
+    }
+);
 
 db.run("CREATE TABLE IF NOT EXISTS stats ( " +
     "id INTEGER NOT NULL, " +
@@ -161,6 +192,12 @@ db.run("CREATE TABLE IF NOT EXISTS stats ( " +
     "net_in REAL NOT NULL, " +
     "net_out REAL NOT NULL, " +
     "block_in REAL NOT NULL, " +
-    "block_out REAL NOT NULL)");
+    "block_out REAL NOT NULL)",
+    function (err, result) {
+        db.run("CREATE INDEX IF NOT EXISTS stats_ts ON stats(ts)");
+        db.run("CREATE INDEX IF NOT EXISTS stats_id ON stats(id, ts)");
+    }
+);
+
 
 setTimeout(main, INTERVAL * 1000);