Welcome back. We're going to continue to work on language that we use to describe data. In this lesson, we're going to learn the language you'll need to describe trends and use vocabulary related to changes over time. You may have heard the word trend or trendy related to something that's popular, but for our purposes that is describing data, a trend is a change over time. For example, you can have an upward trend or downward trend in something. A trend usually means that there were some minor ups and downs, but overall things moved in one direction. For example, there was an upward trend in travel to Cuba last year, or there's been a downward trend in airline ticket sales over the past six months. You could also say a decline or a gradual decrease or increase. Notice that the preposition in is used with the following noun that had the change. There's been a gradual increase in the number of visitors. We saw a decline in sales. And notice that we introduced these noun phrases with expressions like there was or we saw. Many of the nouns we use for changes are also verbs. We'll talk more about verbs in a few minutes. The word decline and its opposite growth are often used with words related to the economy. And sometimes we don't use an article before growth. We usually say there was a decline in interest rates. We saw growth in the economy.

We can add information about the kind of change with expressions like these. A sharp decline, steady growth, and of course we use the noun's increase and decrease. Drop means a sudden change downwards. We took advantage of the drop in prices. The drop in the number of tourists was bad news for business. A sudden change upwards might be called a jump or an uptick. The jump in oil prices caused panic in the market. The uptick in the price of gas for aid consumers. And a very short jump is sometimes called a spike. A spike is usually temporary. There was a spike in the number of phone calls after the new product was announced.

Okay, let's move on to verbs. The words increase and decrease are very common as our rise and fall or go up and go down. The number of tourists increased. The percentage decreased. Inflation rose last year. Interest rates fell. Unemployment went down in the last quarter. Salaries went up. Notice that we only used up and down with the verb go. Do not say the market grew up. Notice that these verbs are all active, not passive. They show a change that happened in the data. Also, be careful about the difference between these two verbs rise and raise. The best way I can think of to remember is that the longer verb can take an object. The shorter verb with only four letters does not take an object. As you've seen in the examples, we often use adjectives and adverbs to describe the degree of change. How much or how quickly something changed. Small and slight are similar in meaning, not very much. Huge, of course, means very large and significant means large or important. Gradual means that something happens slowly over time. Notice that these adjectives showing degree of change go before the nouns. A small change. A slight increase. A huge drop. A very significant decrease. A fairly significant decrease. A gradual change.

We use adverbs to show the degree of change also. They come after the verbs. There was a significant increase. Salaries rose significantly. The number of visitors increased slightly. Costs increased dramatically. Sales fell sharply. Costs went down a slight amount. They declined a bit. Costs increased quite a lot. Okay, now we get into prepositions that we use to describe trends. Here are some that might be very familiar to you. Prepositions and expressions of time. In that period, during the first quarter of the year, between March and June, from March to June, we also use from and to to show a change from one number to another. Sometimes we only point out one end of the change. For example, their market share increased to 45%. Notice again the use of the preposition in to show what the change was in. If you want to say how much, then you use the preposition of after a noun. However, after a verb used by or no preposition. Notice the difference in these two sentences. Ticket prices increased by $50. Ticket prices increased to $50. So in which sentence is the price now $50? Sentence A, because the price changed from one price to another. In sentence B, the price is now $50 more than it was to begin with because it changed by $50.

Sometimes you may be able to use these verbs that illustrate multiples. The number of visitors doubled. Sales tripled in the second year. If there's a lot of up and down movement, you can use the verb fluctuated. If they go up and down and then become flat, you can say leveled off. The number of users fluctuated at first. Then it leveled off. When something stays about the same, you can use the verb stay or remain. We often pair these with the word steady. Sales remained or stayed steady even during the recession. And here are some other less common verbs that great words for illustrating certain changes. The number of visits peaked at $250,000. Visits reached a high of $250,000 in 2012. Visits reached a peak of $250,000 in 2012. Then the number of visits dropped to a low of $47,000. Visits dipped below $100,000 in 2015.

Be careful about verb tense and agreement when you describe data. This sentence has two mistakes. The word sales is plural. So you can't use is. And simple present could be used. For example, when you talk about a percentage, younger people go online more often than older people. But when you talk about a trend, it's not usually in the simple present. A lot of the time, we're describing data that's historical. That is, it happened in the past. See your verbs will be in the past. Sales declined between January and March. If the trend is still happening or had no definite time in the past, use the present perfect or the present perfect progressive. Sales have declined over the past few months. Sales have been declining recently. Sometimes you're describing a trend or change that's taking place right now. Then you might use the present progressive to show that it's a situation that's still in progress. As you can see in this chart, older people are now buying online more frequently. And be sure, no matter which verb tense that this subject in verb agree.