diff --git a/common-tools/clas-detector/src/main/java/org/jlab/detector/calib/utils/OccupancyTable.java b/common-tools/clas-detector/src/main/java/org/jlab/detector/calib/utils/OccupancyTable.java
new file mode 100644
index 0000000000..4d00191d88
--- /dev/null
+++ b/common-tools/clas-detector/src/main/java/org/jlab/detector/calib/utils/OccupancyTable.java
@@ -0,0 +1,108 @@
+package org.jlab.detector.calib.utils;
+
+import java.util.Map;
+import org.jlab.io.base.DataBank;
+import org.jlab.io.base.DataEvent;
+import org.jlab.utils.groups.IndexedTable;
+import org.jlab.utils.groups.IndexedTable.IndexedEntry;
+
+public abstract class OccupancyTable {
+
+    public static class DC extends OccupancyTable {
+        public DC() { super(); }
+        public void add(DataEvent e) {
+            DataBank b = e.getBank("DC::tot");
+            if (b == null) b = e.getBank("DC::tdc");
+            if (b == null) return;
+            final int rows = b.rows();
+            for (int i=0; i<rows; i++)
+                add(b.getByte(0, i), b.getByte(1,i), b.getByte(2,i));
+        }
+    }
+
+    protected String[] valueNames = {"occ/F"};
+    protected String[] indexNames;
+    protected IndexedTable table;
+
+    public OccupancyTable(String... index) {
+        indexNames = index;
+        table = new IndexedTable(indexNames.length, valueNames);
+    }
+
+    public OccupancyTable() {
+        indexNames = new String[]{"sector","layer","component"};
+        table = new IndexedTable(indexNames.length, valueNames);
+    }
+
+    /**
+     * Get the occupancy table.
+     * @param events number of events that have been added
+     * @return 
+     */
+    public final IndexedTable getOccupancy(int events) {
+        IndexedTable t = new IndexedTable(indexNames.length, new String[]{"occ/F"});
+        for (long hash : ((Map<Long,IndexedEntry>)table.getList().getMap()).keySet()) {
+            t.addEntry(IndexedTable.DEFAULT_GENERATOR.getIndices(hash, indexNames.length));
+            t.setDoubleValueByHash((table.getDoubleValueByHash(0, hash))/events, 0, hash);
+        }
+        return t;
+    }
+
+    /**
+     * Reset occupancy table.
+     */
+    public final void reset() {
+        table = new IndexedTable(indexNames.length, valueNames);
+    }
+
+    /**
+     * Fill occupancy table.
+     * @param index 
+     */
+    public final void add(int... index) {
+        final long hash = IndexedTable.DEFAULT_GENERATOR.hashCode(index);
+        if (!table.hasEntryByHash(hash)) {
+            table.addEntry(index);
+            table.setIntValueByHash(0, 0, hash);
+        }
+        table.setDoubleValueByHash(table.getDoubleValueByHash(0, hash) + 1, 0, hash);
+    }
+
+    /**
+     * Get number of rows for the occupancy bank.
+     * @return rows 
+     */
+    public final int getRows() {
+        return table.getRowCount();
+    }
+
+    /**
+     * Update an occupancy bank, assuming 3/4-index s/l/c[/o].
+     * @param bank occupancy bank
+     */
+    public final void update(DataBank bank) {
+        int i = 0;
+        Map<Long,IndexedEntry> m = table.getList().getMap();
+        for (long hash : m.keySet()) {
+            int[] indices = IndexedTable.DEFAULT_GENERATOR.getIndices(hash, indexNames.length);
+            bank.setByte(0, i, (byte)indices[0]);
+            bank.setByte(1, i, (byte)indices[1]);
+            bank.setShort(2, i, (short)indices[2]);
+            if (indexNames.length == 4) bank.setByte(3, i, (byte)indices[3]);
+            bank.setFloat(indexNames.length, i, m.get(hash).getValue(0).intValue());
+            i++;
+        }
+    }
+
+    /**
+     * Create occupancy bank, assuming 3/4-indexing, and add it to the event. 
+     * @param event
+     * @param bank 
+     */
+    public final void update(DataEvent event, String bank) {
+        DataBank b = event.createBank(bank, getRows());
+        if (event.hasBank(bank)) event.removeBank(bank);
+        update(b);
+        event.appendBank(b);
+    }
+}
\ No newline at end of file
diff --git a/common-tools/clas-utils/src/main/java/org/jlab/utils/groups/IndexedList.java b/common-tools/clas-utils/src/main/java/org/jlab/utils/groups/IndexedList.java
index 21b9aca355..384e2cb259 100644
--- a/common-tools/clas-utils/src/main/java/org/jlab/utils/groups/IndexedList.java
+++ b/common-tools/clas-utils/src/main/java/org/jlab/utils/groups/IndexedList.java
@@ -334,6 +334,19 @@ public int getIndex(long hashcode, int order) {
         public int[] getIndices(long hashcode, int... indices) {
             int[] ret = new int[indices.length];
             for (int i=0; i<ret.length; i++)
+                ret[i] = getIndex(hashcode, indices[i]);
+            return ret;
+        }
+
+        /**
+         * Retrieves an array of the indices.
+         * @param hashcode
+         * @param nindices
+         * @return 
+         */
+        public int[] getIndices(long hashcode, int nindices) {
+            int[] ret = new int[nindices];
+            for (int i=0; i<nindices; i++)
                 ret[i] = getIndex(hashcode, i);
             return ret;
         }
diff --git a/common-tools/clas-utils/src/main/java/org/jlab/utils/groups/IndexedTable.java b/common-tools/clas-utils/src/main/java/org/jlab/utils/groups/IndexedTable.java
index 28dcdf629d..a82bd23715 100644
--- a/common-tools/clas-utils/src/main/java/org/jlab/utils/groups/IndexedTable.java
+++ b/common-tools/clas-utils/src/main/java/org/jlab/utils/groups/IndexedTable.java
@@ -167,6 +167,10 @@ public void setIntValueByHash(Integer value, int column, long hash) {
         this.entries.getItemByHash(hash).setValue(column, value);
     }
 
+    public void setDoubleValueByHash(Double value, int column, long hash) {
+        this.entries.getItemByHash(hash).setValue(column, value);
+    }
+
     public int getIntValueByHash(int index, long hash) {
         return entries.getItemByHash(hash).getValue(index).intValue();
     }
diff --git a/etc/bankdefs/hipo4/occupancy.json b/etc/bankdefs/hipo4/occupancy.json
new file mode 100644
index 0000000000..c89164248d
--- /dev/null
+++ b/etc/bankdefs/hipo4/occupancy.json
@@ -0,0 +1,14 @@
+[
+    {
+        "name": "DC::occ",
+        "group": 20600,
+        "item": 20,
+        "info": "Event Header Bank",
+        "entries": [
+            { "name":"sector"    , "type":"B", "info":"sector"},
+            { "name":"layer"     , "type":"B", "info":"layer"},
+            { "name":"component" , "type":"S", "info":"component"},
+            { "name":"hits"      , "type":"F", "info":"number of hits"}
+        ]
+    }
+]