sentance = "Believe it or not, there are still people who are not online! In the US as of 2015, 15% of all adults aged 18+ were not online [Perrin and Duggan, 2015]. A much higher percentage of older adults than younger adults are not online (19–42% vs. 4–7%) [Perrin and Duggan, 2015]. Of all off-liners, 32% cited usability issues: “finding it too difficult or frustrating to go online, or saying that they don’t know how or are physically unable” [Zickuhr, 2013]. Other reasons included high cost, no perceived benefit, and lack of access or availability.But many other people aged 50+ have used digital technology, in some form and to some extent, for decades. They may own computers, tablets, smartphones, e-readers, and fitness trackers. Some of these older adults are casual users (email, shopping, videos), while others have very high levels of technical expertise. Why do some older adults have a hard time with technology?"
words = sentance.split()

word_counter = {}
for word in words:
    if word in word_counter:
        word_counter[word] += 1
    else:
        word_counter[word] = 1

popular_words = sorted(word_counter, key = word_counter.get, reverse = True)


print(popular_words)