Sold products % by category

soldprod.php

<?php

require_once("app/Mage.php");
Mage::app();

$orders = Mage::getModel('sales/order')->getCollection();
$i = 0;
foreach ($orders as $key => $order) {
    if (!$i) {
        $startDate = strtotime($order->getCreatedAt());
    }
    foreach ($order->getAllItems() as $itemId => $item) {
        $_product = Mage::getModel('catalog/product')->load($item->getProductId());
        $catId = array_shift($_product->getCategoryIds());
        $categoryItemIds[$catId][] = $item->getProductId();
    }
    $i++;
}

foreach($categoryItemIds as $catId=>$itemIds) {
    $itemIds  = array_unique($itemIds);
    $cat = Mage::getModel('catalog/category')->load($catId);
    $products = Mage::getResourceModel('reports/product_collection')->addAttributeToFilter('status', array('eq' => 1))->addCategoryFilter($cat)->addAttributeToSelect(array('entity_id'))->load();
    echo "\nCategory ".$cat->getName().": we have sold " . count($itemIds) . " of the " . count($products) . " (" . round((count($itemIds) / count($products) * 100), 2) . "%) visible products in this store in the past " . floor((date("U") - $startDate) / 86400) . " days, spread out over " . count($orders) . " orders\n";
}