Gregor Mendel studied the inheritance of traits in pea plants. One trait he examined was the height of the plant. Pea plants with the dominant 'T' allele grew tall, and pea plants with the recessive allele 't' were short. According to Mendel's principles of heredity, if a homozygous tall pea plant was crossed with a homozygous short pea plant, approximately how many of their offspring would have the short phenotype?