Section 906 Certifications - --------------------------- I, Charles E. Porter, a Principal Executive Officer of the Funds listed on Attachment A, certify that, to my knowledge: 1. The form N-CSR of the Funds listed on Attachment A for the period ended July 31, 2005 fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and 2. The information contained in the Form N-CSR of the Funds listed on Attachment A for the period ended July 31, 2005 fairly presents, in all material respects, the financial condition and results of operations of the Funds listed on Attachment A. /s/ Charles E. Porter -------------------------- Date: September 27, 2005 Charles E. Porter Principal Executive Officer Section 906 Certifications - --------------------------- I, Steven D. Krichmar, a Principal Financial Officer of the Funds listed on Attachment A, certify that, to my knowledge: 1. The form N-CSR of the Funds listed on Attachment A for the period ended July 31, 2005 fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and 2. The information contained in the Form N-CSR of the Funds listed on Attachment A for the period ended July 31, 2005 fairly presents, in all material respects, the financial condition and results of operations of the Funds listed on Attachment A. /s/ Steven D. Krichmar ------------------------------- Date: September 27, 2005 Steven D. Krichmar Principal Financial Officer Attachment A - ------------------------------------- N-CSR Period (s) ended July 31, 2005 Annuals - ------------------------------------- 003 Putnam Investors Fund 007 Putnam Voyager Fund 073 Putnam Premier Income Trust 035 Putnam AMT Free-Insured Municipal Fund 2AQ Putnam Research Fund 2AP Putnam Growth Opportunities Fund 036 Putnam Tax Free High Yield Fund 001 The George Putnam Fund of Boston 006 Putnam Vista Fund 024 Putnam OTC & Emerging Growth Fund Putnam RetirementReady Funds - ------------------------------------- 48P Putnam RetirementReady Maturity 48I Putnam RetirementReady 2010 48W Putnam RetirementReady 2015 49D Putnam RetirementReady 2020 49K Putnam RetirementReady 2025 49R Putnam RetirementReady 2030 49Y Putnam RetirementReady 2035 40F Putnam RetirementReady 2040 40M Putnam RetirementReady 2045 7CR Putnam RetirementReady 2050