Looking at the entire company, our core portfolio occupancy was 86.5% up 110 basis points since 2010 year end. We also ended the year 89.5% leased up 180 basis points from the beginning of the year and we are maintaining a very healthy 300 basis points of lease to occupied spread. Our tenant retention rate for the year came in at 65% versus our original plan of 56%. We also had net absorption during the year of over 277,000 square feet. A real step in the right direction and compared to negative absorption of over 600,000 square feet during 2010 so our portfolio is definitely on the right track.
In 2011 we experienced rental rate declines on both a GAAP and cash basis far from acceptable but both significant improvements from 2010 levels. Additionally, our leasing capital cost per square foot trended higher during the year and elevated capital spending remains a key focus for the company and George will address this in more detail during his comments.
During 2011 our average lease term increased to six years, up from our business plan forecast of four years. We plan continued negotiation for longer term leases with built in annual escalators ranging from 1.5% to 3% to offset larger upfront capital commitments. The portfolio is in much better position entering 2012 and this success we had during ’11 reflects the quality and location of our portfolio, a steadily recovering market, the skills of our leasing and property management teams and our continuing focus on market outperformance.
Now, looking at our balance sheet, as we entered 2011 we faced significant debt maturities over $500 million with $400 million of our debt exposed to floating rates, or about 20% of our total debt. Our primary objective during 2011 was to stabilize our financial platform by eliminating debt maturity risk and protecting future EBITDA improvement from interest rate volatility.