Table 1: Absolute (upper panel) and relative (lower panel) numbers of YSOs of different classes from observations (references see text).
Region Prestellar 0 1 2 3

$\rho$ Oph 98 2 15 111 77

Serpens 26 5 19 18 $\sim$ 20

Taurus 52 3 25 108 72

Cha I <71 2 5 175

IC 348 2 2 261

NGC 7129 1 20 80

IC 1396A 2 6 47 1

$\rho$ Oph 0.01 0.07 0.92

Serpens 0.08 0.31 0.61

Taurus 0.01 0.12 0.87

Cha I 0.01 0.03 0.96

IC 348 0.01 0.01 0.98

NGC 7129 0.01 0.20 0.79

IC 1396A 0.03 0.11 0.86

**Table 1:** Absolute *(upper panel)* and relative *(lower panel)* numbers of YSOs of different classes from observations (references see text).
Region	Prestellar	0	1	2	3
$\rho$ Oph	98	2	15	111	77
Serpens	26	5	19	18	$\sim$ 20
Taurus	52	3	25	108	72
Cha I	<71	2	5	175
IC 348		2	2	261
NGC 7129		1	20	80
IC 1396A		2	6	47	1
$\rho$ Oph		0.01	0.07	0.92
Serpens		0.08	0.31	0.61
Taurus		0.01	0.12	0.87
Cha I		0.01	0.03	0.96
IC 348		0.01	0.01	0.98
NGC 7129		0.01	0.20	0.79
IC 1396A		0.03	0.11	0.86

Source LaTeX | All tables | In the text

	1 Introduction
	2 Observational data
	3 The models
	4 Discussion
	5 Summary and conclusions
	References