Internet Explorer
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http://secunia.com/product/11/
ctrl+f  List of Patched/Unpatched Secunia Advisories
Microsoft Internet Explorer 6 with all vendor patches installed and all vendor workarounds applied, is currently affected by one or more Secunia advisories rated Extremely critical
Unpatched 33%
Extremely and highly critical vulnerabilites - 49%

Mozilla Firefox
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http://secunia.com/product/3256/
Mozilla Firefox 0.x with all vendor patches installed and all vendor workarounds applied, is currently affected by one or more Secunia advisories rated Less critical
Unpatched 19%
Extremely and highly critical vulnerabilites - 13%

Opera
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http://secunia.com/product/761/
Opera 7.x with all vendor patches installed and all vendor workarounds applied, is currently affected by one or more Secunia advisories rated Moderately critical
Unpatched 4%
Extremely and highly critical vulnerabilites - 15%

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