mismatch between Perl 5.6 and Perl 5.8 in printing high precision values.

printf("%.32g\n",0.99999999976 716936); Perl 5.6.1 output: 0.99999999976716936 --> GOOD Perl 5.8.6 output: 0.99999999976716925 --> ERROR Any reason for such mismatch ? Please let me know how to avoid that or any alternative approach if any. Thanks Vivek