randomly generating and controlling the value for sqlite database in PHP

hi guys i got this sqlite database which has only one 1 row called revenue_value and it has 2000 value. Lets say i click generate value button and generates 12 random number and i know rand will randomly generate values but all i want to know is can i control that randomness value for example - 2000 is the base value but at the end it has to end up with 20% higher than 2000 but in between value can go down or up.

i got the table working data.php

<?php
try
{
$db = new PDO('sqlite:randvalue.sqlite');
$db->exec("CREATE TABLE company (revenue_value INTEGER PRIMARY KEY)");

$db->exec("INSERT INTO company(revenue_value) VALUES ('2000')");

print "<table border=1>";
print "<tr><td>value</td></tr>";
$result = $db->query('SELECT * FROM company');

foreach($result as $row)
{
    print "<tr><td>".$row['revenue_value']."</td></tr>";
}
print "</table>";

$db = NULL;

}

catch(PDOException $e)
{
    print 'Exception : '.$e->getMessage();
}

?>

and the rest of the code is ajax.js which will echo it to index.php

any ideas guys