An adequate lifestyle for a retired couple

I carried out a survey two months ago to ask about the monthly expenses for a retired couple. Only 5 people participated in the survey. Here are the results. Please note that due to the small sample, the results may be unreliable:

Utilities and other expenses for HDB flat                $386
Food for a couple                                                 $450
Medical expenses                                                 $256
TV, internet, telephone                                         $124
Public transport                                                    $88
Travel and holiday                                                $414
Gifts                                                                     $67
Total                                                                    $1,785 (say $1,800)

If the retired couple owns a car, the monthly expenses goes up by another $600. If they skip holidays, the expenses drop by $400.