H1B cap exempt petition status

Hi All,

I have travelled on my H1B in October 2012 and worked there till May 2014 and came back to India. My petition and stamping got expired on September 2014. Later the same employer filed cap exempt for my H1B and my petition got filed on 19th November. It is almost six months now, but USCIS still shows my petition status as ‘My case was received’. Could any one please suggest how long it will take for my approval and is this common to have cap exempt petition pending with USCIS for more than 5 to 6 months.